Sentience in fish

Studies of mental functions, behaviors and the nervous system.

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Re: Sentience in fish

#81  Postby cavarka9 » Jul 31, 2011 3:31 pm

rEvolutionist wrote:Huh? Who's the "him" in: "Thanks samsa, but I could have guessed that there was no hope in pursuing to push him on these issues, I learned that when I argued about genes and intelligence with regards to a 12yr old(news)"?

samsa from another context.
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Re: Sentience in fish

#82  Postby natselrox » Jul 31, 2011 5:53 pm

rEvolutionist wrote:Huh? Who's the "him" in: "Thanks samsa, but I could have guessed that there was no hope in pursuing to push him on these issues, I learned that when I argued about genes and intelligence with regards to a 12yr old(news)"?


Mr. Second Language.
When in perplexity, read on.

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Re: Sentience in fish

#83  Postby cavarka9 » Jul 31, 2011 6:07 pm

natselrox wrote:
rEvolutionist wrote:Huh? Who's the "him" in: "Thanks samsa, but I could have guessed that there was no hope in pursuing to push him on these issues, I learned that when I argued about genes and intelligence with regards to a 12yr old(news)"?


Mr. Second Language.

I saw that :grin: . You shouldn't go telling that to people, must let them work it out on their own, they can see the flag.
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Re: Sentience in fish

#84  Postby natselrox » Jul 31, 2011 6:26 pm

:lol:

engleesh sucks...
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Re: Sentience in fish

#85  Postby cavarka9 » Jul 31, 2011 6:40 pm

natselrox wrote::lol:

engleesh sucks...

:naughty: ,no it doesnt suck and young kids like you need to work on your spellings ,It is 'Inglisch'.
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Re: Sentience in fish

#86  Postby Calilasseia » Jul 31, 2011 8:47 pm

I've mentioned what is known in fishkeeping circles as "The Venerable Innes Book" in earlier posts in this thread, which contains an account of Cichlid breeding, the details of which are fascinating to observe, and which provide much delight to fishkeepers around the world, as they have done in the aquarium hobby for over 80 years. Indeed, the first Cichlid domesticated in the aquarium, the Argentine species Austroheros facetos, known colloquially as the Chanchito, was domesticated in 1884, and captive breeding followed soon afterwards. The tolerance of this species for temperatures as low as 60°F was undoubtedly a factor in its selection as an aquarium fish, in an era when aquarium heating technology was rudimentary to put it mildly. However, once heating technology became both affordable and reliable, a range of Cichlid fishes were added to the aquarium list, the primary choices being fishes from Central America, not least because of the close proximity of places such as Mexico and Honduras to the United States, which still remains the largest single market for aquarium fishes. The readiness of these fishes to breed in the aquarium, and in the case of the southern US states, to breed in outdoor ponds in summer, soon ensured that the aquarium market no longer needed to procure wild stocks, indeed the fecundity of many Cichlids is such that they produce a surplus for that market, and prices for the popular species are accordingly low. However, what is of interest here is not the details of the aquarium market, but the behaviour of these fishes, and its relevance to the question of fish sentience, and it is because of this that I turn to pages 363 to 367 of Innes' Exotic Aquarium Fishes, which contains a detailed description thereof.

Before I reproduce this section of this work, for everyone's delight and delectation, I advise people to exercise some care with what follows, courtesy of the fact that the first edition of Innes' work was first published back in 1936, and much additional knowledge about fish behaviour has been acquired since then. Accordingly, I have annotated the account below with appropriate footnotes, and after I have reproduced the article and the footnotes, I'll add some more modern observations in order to provide a fuller picture of Cichlid breeding behaviour, which, I think everyone will agree, is pretty sophisticated.

And so, to the article!

Breeding

With the unique exception of the mouthbreeders1 (whose habits will be described under their own headings), the Cichlids breed so nearly alike2 that a general description will fit nearly all of them.3 The few traits that may be peculiar to a species will be noted under its own special text. For example, that popular ruling favourite, Pterophyllum scalare, requires separate consideration.4

The typical breeding actions of Cichlids are certainly the most interesting and highly organised of any known aquarium fishes,5 especially when the habits of mouthbreeres are added to that which now follows.

Mating itself with them is no hit-or-miss affair. At the very beginning the ancient law of the survival of the fittest6 is put into practical operation. If left to themselves in a large group, pairs will mate themselves by natural affinity, which is one of the best ways of discovering pairs if one has the room and stock to carry out this plan. The usual procedure in trying to mate a pair with a minimum of risk is to place them in a large aquarium with a glass partition between. That is their formal introduction. One fish is usually ready to mate before the other, and as flirtation through windows is nothing new in this world,[sup7[/sup] one of them makes the opening advances. As again in our world, it may be either the male or the female to make the first move.8 This consists of a wagging of the body, spreading of the fins and a variety of changes in colouring.9

When the "party of the second part" returns these salutations and shows signs of approval, it is time to take out the partition and note what happens. Usually the courtship continues and it is not long before the kissing stage develops.10 This is where one of the uses of strong jaws comes in. They grasp each other by interlocking the lips and then begins the first real test. Each tugs and twists the other, apparently in a test of strength. They may go through the performance several time. If they do this repeatedly without either losing its "nerve", they may be considered to be as well mated as though they have a marriage certificate.11 But it often happens that one of them takes fright and beats a retrerat after one of those vigorous kisses. Fear is fatal, and the victim of it is liable to get killed unless a safe retreat is found, or a kind Fate in the person of the owner separates them.

Sometimes a subsequent trial will prove more successful, but it is advisable to try some other pairing, if substitutes are on hand. Certain fishes will reject or kill several proposed mates before meeting an agreeable affinity.12

Owing to the physical tussle which takes place, an effort is usually made by the aquarist to match the candidates in size, but there are many instances of happy unions between fishes where disparity in this respect is great.13 Whether or not both fishes are ready to mate is the important thing. Their courtship promotes elimination of the unfit.14

This matter of the mating having been gone into so thoroughly by the contracting parties, one naturally expects that a good old-fashioned, non-divorce marriage is in the making,15 and for the most part that is true. It may be taken for granted that a water lily pool 5 feet square or larger is equivalent to natural conditions.16 In mild climates most Cichlids placed in such a pool in the beginning of summer17 will, if well fed, breed throughout the warm season. From this it is fair to assume that even in their native tropical habitat, where there is no cold or even cool season, the mating lasts indefinitely, as with pigeons.18 The actions of animals in the usual restricted space provided in captivity are seldom entirely normal. It is therefore not surprising that in the average aquarium these matings sometimes come to an abrupt end - usually in a quarrel over domestic matters.19

To return to the actuall business of breeding - let us consider the proper conditions which should be provided. Success is more likely in large aquaria. Among the larger species, 3 inches is minimum breeding size.20 Such fishes should be bred in an aquarium of not less than 10 gallons. Twenty would be better. As the size of the pair increases, follow with proportionate room.. It will pay.21

Water should be old22 and at a temperature between 78 and 85 degrees [Fahrenheit]. The best bottom covering is approximately 2 inches of well-washed sand.23 Any moderately good light is satisfactory. Omit plants for most species. Exceptions in this respect will be noted.

For a few days prior to breeding, the fishes dig holes in the sand. They also start cleaning a surface which they regard as suitable for the reception of their adhesive eggs. This spot may be on the side of the aquarium, a large stone, the inside or outside of a flower-pot laid on its side, or even a spot on the aquarium bottom from which sand has been fanned away.24 It has been observed that a light-coloured surface is preferred to dark. For this reason some of our fish breeders place a piece of marble or other light-coloured stone in the aquarium with mated Cichlids.25

The breeding pair takes nothing for granted as to cleanliness. Regardless of whether they select a mossy side of the aquarium or a piece of marble fresh from the quarry, the sacred spot to recieve their eggs must be painstakingly gone over to insure its absolute cleanliness. They bite, scrape and polish it with their mouths until no flaw can be found. No Dutch housewife could make it cleaner.26

A day or two prior to the actual spawning both fish develop from the vent a breeding tube, or ovipositor. It first appears as a very small point or nipple. Whether it is a Cichlid or certain other species which deposit their eggs in a like manner, the appearance of the nipple is regarded as a sure sign that the fish is ripe for breeding. The tube shortly before spawning increases in length. In large specimens it may be as long as a half inch.

All things now being in readiness, the female approaches the prepared breeding spot and touches it lightly with the breeding tube, depositing one or more eggs. The male immediately follows and with a like action sprays the eggs with his fertilising fluid. This is repeated many times over a period of 2 hours, when finally there may be from 100 to 500 eggs laid in close formation. As this whole operation is carried on by a sense of touch and the eggs adhere very lightly, it is quite remarkable how few are lost or knocked off.27

The spawning operation being completed, each fish takes turn fanning the eggs with the breast fins or tail. They relieve each other every few minutes. It is a popular idea that this fanning is to supply oxygen to the embryo within the egg, but it seems unlikely that oxygen could penetrate the firm skin within which it is enveloped.28 As fungus is the great enemy of the eggs29 and the parents go to no end of trouble to have everything immaculate, presumably to avoid this danger, it seems likely that they are preventing fungus-bearing particles of dirt from settling on the spawn. Sometimes, despite care, fungus develops on a few eggs. It attacks all infertile eggs. Apparently sensing the danger of its spread, the fishes eat the affected eggs. This sometimes ends in all the eggs, good and bad, being eaten.30

At a temperature of 80 degrees [Fahrenheit] the eggs hatch in about 4 days. Now begins the next of the several remarkable stages in the breeding habits of these fishes. Either just before or just after the egg hatches it is carried off in the mouth of either of the parents and deposited in a depression in the sand. It may be newly dug or one left from the home-building connected with the early part of mating.31 The parents alternate in making trips between the hatching place and the depression until all are transferred. In some instances the fishes set up a system so that neither end of the line is left unguarded. Each guard stands at one end and as everything is in readiness for the transfer of young, a signal is given in fish language and they dash past each other to the opposite terminus.32

The young in the depression look like a vibrating, jelly-like mass not very easy to see. For several days they are moved from one depression to another, gently carried in the mouths of the parents. While it is generally conceded that the lower animals do not reason things out,33 the result is often the same as though they do. What they do by "instinct" is often wiser than our actions guided by reason. Whether the apparent reasoning in the action of animals is of their own creation or is a reflection of the Master Mind in Nature34 makes little difference. Reasons for everything exist. It is interesting to speculate on them, and if we attribute higher thinking powers to our friends the fishes than they actually possess, we are only giving them the benefit of the doubt.

Cichlids not only have the most highly developed breeding habits35 from the social standpoint, but combine them with a seeming understanding of certain scientific principles which, as far as Man is concerned, were discovered but yesterday.36 These are the recognition of the dangers from bacteria, and of their control through cleanliness. Reference has already been made to the scrupulous care in cleansing the spawning surface and to the eating of such eggs as have been attacked by fungus. Various interpretations may be placed on the practice of moving the young from one hole to another. As this is begun before the babies are old enough to eat anything, it cannot be to provide new pastures. One hole would be as safe from enemies as any other. Besides, in the open places where these fishes breed, they are absolutely fearless in the defence of their young,37 so the theory of safety may be dismissed.38 The theory which is in line with their other actions points to cleanliness as the motive - scientific cleanliness if you will. The babies are picked up in the mouth, a few at a time, and apparently chewed. They are only rolled around harmlessly and discharged into the next depression. Every last one is so treated. This is the fish's baby bath. Each one emerges perfectly cleansed of any particles. By using a series of depressions for the purpose, the parents are absolutely certain that all babies were "scrubbed", of which one could not be sure if they were kept in one place.

After 8 to 14 days the yolk-sacs of the young have been absorbed and they swim up in a cloud with the parents, usually in formation, headed one way. Stragglers are gathered up in the mouths of the parents and shot back into the chool. This family unity is very beautiful to see and gives the aquarist one of his biggest and most lasting thrills. How long the parents and young should be left together is a question largely of sentiment. In the wild the parents undoubtedly can be of much use to the young by protecting them after they are swimming about, but in the aquarium their usefulness ends at that point. The pleasure of seeing the parents and young together is the only reason for not separating them at once. No hen could be more solicitous for her flock than these devoted fish-parents for their fry. In their defence they are the very embodiment of savage fury, no matter what or how large the real or imagined enemy. The owner himself had better not poke his nose too close to the water when peering into the domestic affairs of a large pair of Cichlids unless he wishes to have it shortened.

Footnotes:

1 The modern term is mouthbrooders, which is a more rigorous description of these fishes.

2 This may have been a valid statement in 1936, when the number of Cichlids known in the aquarium hobby was limited, but has long since been rendered obsolete. Numerous well-defined variations on the basic Cichlid reproductive theme exist even amongst those that do not engage in mouthbrooding behaviour.

3 The "general description" here is actually applicable primarily to certain Central American Cichlid Genera, such as Thorichthys, Archocentrus, Heros, Parachromis, etc., but even so, variations exist on the theme within the Central American species (Herotilapia multispinosa and Neetroplus nematopus being two that have been described in detail by Dr Paul Loiselle, for example).

4 And as I've already remarked above in 2 and 3, this statement is now more or less obsolete in the light of more modern data. However, this does not detract from the fact that the behaviour described in Innes' writing is frequently observed and well-documented in a number of species.

5 Keepers of bubble nest building Anabantoid fishes may wish to dispute this claim, of course.

6 Whilst scientifically literate persons may wince at seeing this old saw erected here, bear in mind that Innes was writing for a lay audience back in 1936, and doing so only 11 years after the Scopes Trial in his native land.

7 One of many quaintly charming anthropomorphisms that litter Innes' writing, though once again, the aim was to inculcate a certain empathy between the aquarium keeper and his fishes, which is something I have been keen to do myself in the world of fishkeeping.

8 An observation that has been replicated countless thousands of times in the aquaria of Cichlid fans around the world.

9 Again, extensive documentation of this exists, both in the informal setting of aquarium hobby magazines, and more formal scientific settings.

10 More correctly, this is known in modern texts as jaw-locking. However, the visual appearance of this process makes the allusion by Innes to human kissing not overly fanciful.

11 With hindsight, it is tempting to regard this as a sop to prurience.

12 Of course, fishes in the wild have much greater opportunity of escape, and finding an alternative partner, than fishes in an aquarium, but the behaviour observed in the aquarium has also been repeatedly observed in the wild. It is a testament to the adaptability of these fishes, that they can exhibit their natural behaviour in highly artificial surroundings, without showing undue modification thereof.

13 Again, observed on numerous occasions over the past 80 or more years of the aquarium hobby.

14 Once again, try not to wince when reading such words, which were written in an era when the understanding of biological phenomena was still being polluted by eugenic ideas.

15 See 11.

16 This assumption was based upon a less than optimal understanding of the requirements of these fishes, and the manner in which they integrate into their wild habitats. Needless to say, old ideas about Cichlid space requirements have long since been superseded by better understanding.

17 Remember that the author wrote primarily for an American audience, and that in some parts of the USA, summertime conditions are sufficiently warm to emulate those found in the native habitats of a good number of Central American Cichlid fishes. Indeed, Herichthys cyanoguttatus has a range that penetrates into southern Texas naturally, and consequently, will be at home in a pond in the southernmost US states. This is most definitely not the case in Europe, except during particularly warm summers!

18 More correctly, mating and producing offspring in some Cichlid species is triggered by cues arising from the transition from the wet season to the dry season. Though in some habitats, year-round mating has indeed been documented, including in species more usually regarded as being seasonally cued.

19 For someone writing for a lay audience (and, courtesy of the socio-political environment extant at that time, an audience almost certainly ignorant of much real biological fact), this particular piece of understanding is commendable.

20 This may be the case in the species known to Innes in 1936, but again, this has long since been superseded in the case of the biggest Cichlid species kept regularly in aquaria, such as Parachromis managuensis and Parachromis dovii.

21 Most modern Cichlid keepers will almost certainly laugh at the idea of even trying to physically fit a pair of Parachromis dovii in a 10 gallon aquarium, let alone persuadee them to breed therein! For this species, the recommendation is not less than 300 gallons. Note at this juncture that Innes is, as might be expected, referring to US gallons, which are smaller than UK gallons, which makes the remarks even more hilarious in the light of modern knowledge, because Parachromis dovii requires 300 UK gallons simply for routine maintenance, and captive breeding is best attempted in even larger sized aquaria!

22 Here, "old" means "previously matured in an aquarium", and consequently free of the various additives that are usually found in tap water. There are modern methods of achieving an appropriate result in much shorter time.

23 Actually, optimum choice of substrates may vary considerably from species to species - some live naturally in water bodies with sandy substrates, others in water bodies with a gravel substrate, and yet others live out their lives over a substrate of sizeable pebbles. In the case of some African Cichlids, their "substrate" consists of boulder screes whose component rocks may be the size of a large detached house!

24 The digging activities of many Cichlids is an interesting aspect of their breeding behaviour, which Innes will come to in more detail later. Suffice it to say that these fishes, motivated as they are by sex, can on occasions be truly prodigious excavators in relation to their size, and possess powerful musculature facilitating this even in the smaller species, which is one of the reasons why some aquarists experience hair-tearing frustration, when these fishes remodel the aquarium to suit them, with complete diregard for the owner's aesthetic desires!

25 I admit at this juncture to not knowing if this assertion has been empirically verified, though given that Innes was pretty scrupulous with respect to detail in his work, intending that readers thereof enjoy maximum success with their fishkeeping, this is an idea that may be regarded as being of reasonable prrovenance.

26 Whilst the remarks about Cichlid attention to egg-laying surfaces here are valid, one is once again forced to smile at Innes' choice of folk imagery.

27 In the case of Parachromis managuensis, a big spawn can result in no less than five thousand eggs being laid. Numerous large Cichlid species have spawn counts in the 2,000 to 2,500 range as large adults.

28 One instance where Innes' knowledge of biology lets him down I'm afraid. If oxygen did not diffuse through the outer integument of the egg, the embryo would most likely die!

29 This time, Innes is spot on. Fungi from the Genus Saprolegnia among others, are a particular danger to fish eggs, though usually they only germinate upon unfertilised eggs. However, in a closely packed egg mass, one unfertilised egg succumbing thereto can act as a vector for the infection of fertilised eggs, and the destruction of the embryos therein. The parent fishes exercise considerable diligence with respect to the matter of seeking to prevent egg fungus spores from settling upon the egg mass.

30 This is most frequently observed amongst neophyte or 'virgin' fishes mating for the first time. Older and more experienced parents are more likely to be selective with respect to the removal of fungus-affected eggs, and indeed, can exhibit a remarkable degree of precision in extracting a single fungus-affected egg from the egg mass - all the more remarkable in the case of big predatory Cichlids, such as Parachromis managuensis, which has mouthparts more suited to butchery than surgical excision!

31 These are the details I referred to in connection with 24 above.

32 Again, behaviour well documented in the literature, though in somewhat less chintzy terms.

33 Again, the vintage of this piece is showing.

34 See 6.

35 See 5, and note also the closely related Pomacentidae, whose breeding behaviour is very similar to that of Cichlids, which should surprise no one familiar with the moelcular phylogeny of the two Families.

36 Innes, while giving the fishes much credit for sophistication of observed behaviour, really does let anthropomorphism run riot at this point.

37 Indeed, put your hand in an aquarium containing breeding Cichlids caring for young, and they will launch an immediate and vigorous attack thereupon! They will even issue threat displays to pet cats and dogs peering through the aquarium glass, and if any such pets are careless enough to try poking their noses in the aquarium water at the top, the fishes will respond unequivocally, with a charge at the intruding nose!

38 Not so fast, Dr Innes! It's entirely possible that the movement of the young is to confuse potential fry thieves, in accordance with the well known principle that the longer the enemy spends working out how to attack you, the less time is available to prosecute the actual attack. In the natural habitat of some of these fishes, nocturnal catfishes do present a threat to the young, and moving the fry about on a regular basis may well be a means of dealing with any nocturnal catfish that memorises a given location, only to come back in the night to steal some fry. Of course, such an analysis doesn't help in the case of chance predators, particularly ones not noted for their memory capacity, but one must exercise care here, something Innes is about to abandon with his immediately following words!


Among the more recent additions to the aquarium list are species such as Herotilapia multispinosa (which, despite containing the word 'tilapia' in the Generic name, is actually a native of Mexico) and Neetroplus nematopus. More detailed descriptions of the specific behaviour of these species has been provided by Dr Paul Loiselle, an ichthyologist and fish taxonomist with a special interest in Cichlids, and it is with reference to his notes, and subsidiary observations by Juan Miguel Artigas Azas, that I shall continue, noting where relvant contrasting behaviours of other species.

In the case of Central American Cichlids, the limiting factor in wild habitats is not water volume, as some of these fishes live in large rivers and lakes. What acts as a limiting factor is the availablility of prime spawning real estate, as it were, because Cichlids have specific, well-defined requirements with respect to their choice of spawning sites, and the number of suitable sites is limited accordingly. As a result, competition in some habitats for prime locations is, quite literally, cut-throat, and as a consequence, Cichlids have evolved to be strongly territorial fishes. These fishes know what they want, and are motivated powerfully to get what they want, a factor that causes much grief in the aquarium if the fishkeeper doesn't plan ahead for this. As a consequence, different species have adopted different approaches to the problems faced by such issues as crowding.

For example, Herotilapia multispinosa has adapted to occupy waters rejected by many other Cichlids, including small creeks and streams suffering from eutrophication, and, since they face little competition from other Cichlids in these bodies of water, they have developed a tendency to exhibit less aggression than many other Centrl American Cichlids. This is presumably on the basis, that starting a fight in a seriously crowded body of water risks escalation into full-scale internecine warfare, which would be detrimental to the species as a whole, and so, this species places fewer demands on space than other Central American Cichlids of similar size, and is much less inclined to suffer from the descent of the red mist in a crowded situation. The turbidity of their home breeding waters in numerous instances also contributes to this - they are less likely to see rivals across distances than occupants of crystal clear waters. On the other hand, members of the Genus Nandopsis, which in the main are large, predatory fishes that cruise open waters, and which are pretty close to being apex predators amongst the fishes in their ecosystems, have evolved to spawn out in the open, where life is considerably more perilous than in reedy shallows, and these fishes are, as a consequence, far more aggressive - indeed, failure to take account of this in an aquarium leads to these fishes becoming savage aquarium terrorists at the drop of a hat. Lying somewhere in between these ends of the spectrum are fishes such as Archocentrus nigrofasciatus, which still has a reputation for being a pugnacious little fish, Rocio octofasciata, whose willingness to get into a fight earned it the common name of "Jack Dempsey", an allusion to a particularly belligerent former World Heavyweight Champion boxer, and Thorichthys meeki, which tends to be at the lower end of the scale, but still a force to be reckoned with if it decides that combat is in order.

Whilst the physical size of these fishes when fully grown varies (from 12 cm for Herotilapia multispinosa, to 50 cm for Parachromis managuensis, and a whopping 90 cm for Parachromis dovii, known appropriately as the Wolf Cichlid upon account of its predatory behaviour), the behaviour patterns are usually variations on the theme Innes presented in the above reproduced article, those variations being a result of niche migration that in some cases follows trophic specialisation, but a full discussion of this is beyond the scope of this post. However, in general, Nandopis, Parachromis, Rocio and their South American analogues in the Genus Caquetaia, along with the Green Terror from the Peruvian Amazon, Aequidens rivulatus, are large, aggressive open water spawners that are best described as "take no prisoners" fishes, whilst Archocentrus reproduce the open water spawning behaviour (and to a lesser extent, the aggression) in smaller, shallower bodies of water, whilst Thorichthys is more likely to spawn close to reed beds, and fishes such as one or two members of the Genus Theraps utilise cave-like features as nurseries for their eggs instead of flat rocks in open water. These variations aside, spawning follows the Innes model pretty closely in all of these fishes.

Likewise, when it comes to the matter of guarding the free-swimming fry, these fishes adopt the "convoy escort" strategy, the parents staying close to the fry, either side of the little shoal, keeping watch for potential or actual incoming threats, acting like escorting battleships guarding a convoy from surface attack by commerce raiders. In the case of fishes such as Parachromis, the giant predatory guapotes, the sheer size of the parents, plus their position as apex predators upon other fishes, usually suffices to keep most potential fry thieves at bay, whilst the smaller species such as Archocentrus nigrofasciatus tend to require more vigilance, sharing their waters with the predatory livebearing fish Belonesox belizanus, a pike-like opportunist predator upon small fishes that is only marginally larger when fully grown than the parent Archocentrus.

However, there is one exception to this rule, and this exception is a little fish known as Neetroplus nematopus. This fish adopts a completely different strategy with respect to egg and fry protection. Instead of guarding the eggs closely, these fishes adopt a strategy of "prevention is better than cure", and, in the run up to spawning, these fishes ruthlessly enforce an "exclusion zone" around their chosen spawning site. The pair will embark upon "search and destroy" missions, actively hunting for unwanted intruders straying close to their chosen site, and upon finding any, will immediately launch into a "combined arms" attack upon the target - the male launches a head on frontal attack, whilst the female, taking advantage of the distraction provide by the male, goes for the soft underparts. Few fishes stay in the area for long when subject to this determined assault, and the fishes reinforce this conditioning of their neighbours by displaying high-contrast breeding colours, so that other fishes in the vicinity know that these little demon Cichlids are intent upon keeping everything outside their chosen exclusion zone. Neetroplus nematopus will happily attack fishes more than twice its own size (it's a 12 cm fish fully grown), and in an aquarium, will terrorise the other occupants mercilessly once it's decided to raise a family - indeed, the contrast between its relative docility when not breeding, and the seemingly psychotic behaviour it exhibits once a family is imminent, makes for a stark contrast, and a lot of headaches on the part of fishkeepers who fail to plan for this.

Now, as for how much of the above constitutes 'intelligent' behaviour is a subject of active research, though it is known from prior research that Cichlids are capable of learning a surprising amount, if presented with suitable incentives. Indeed, owners of large Cichlids have even performed such tricks as teaching their Cichlids to ring bells for food. Cichlids in an aquarium quickly learn to differentiate between their owner, who supplies the food, and other visitors, who are frequently treated to glowering "back off" territorial displays, and during breeding, if they decide that the aquarium decor is not to their liking, they will set about remodelling the aquarium to suit their own requirements, much to the consternation of aquarists who spend hours lovingly constructing lavish underwater dioramas, only to see their Cichlids launch into full-scale deployment of the wrecking ball upon their efforts. :)

Most people, observing the behaviours I've described above, particularly the monogamous pairing for life, and the manifest displays of intent that these fishes display readily, would regard said behaviours as being "intelligent", particularly when the capacity for learning that these fishes possess is factored in. How much of this behaviour would be rigorously classified as such remains a topic for research, but one thing I can tell you is this - if these fishes are not genuinely "intelligent", they deliver a remarkable simulacrum thereof. :)
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Re: Sentience in fish

#87  Postby Mr.Samsa » Aug 01, 2011 3:34 am

cavarka9 wrote: Absolutely not, I am only saying that the level of exact details in these areas are generally not clear and you are clever enough to lock on to them and the fact that the more we try to know things, the more nuanced the details are, makes it difficult to have any general notion of something, which makes it difficult for people to stand by a hypothesis or a position based on a general assumption. In this case, "sentience" has a lot to do with how people define it. I was only applauding your effort in showing to people that things are not clear as they assumed they were when they began to debate on this issue.
:cheers:


Ah, I get you now. Thanks for explaining, and I'm glad you think my posts are useful in discussions like these :cheers:

rEvolutionist wrote:
Mr.Samsa wrote:I'm not too sure. My general guess is that we were a 'jack of all trades' species - we got lucky with a number of things, opposable thumbs, creation of fire, etc. This led to the capability of language, which led to the development of vast cultural history. I suppose another way to think of it, is that I think that if we could somehow create, say, a "pigeon culture" with a history as vast as ours, with the permanency and transmission of information, then I'd guess that pigeons would be achieving similar things to us.


What's your knowledge of our memory abilities vs some other species? I'd imagine memory must play a part in intelligence as well.


I'm not too sure, to be honest. The best task for assessing memory across species is the radial arm maze - this is basically a maze that is set up like spokes on a wheel (looking from above):

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A trial begins with the subject being placed in the centre, and food is placed at the end of different arms (with procedures in place to prevent subjects using olfactory cues to find food, or to follow their old tracks). This assesses short term memory by calculating how many times the subject goes down an arm where the food had already been eaten within that session, and long term memory is calculated by looking at how many times they go down an arm that never has food in it across sessions.

This paper seems to suggest that mammals and birds all seem to score similarly to humans - with a memory of around 7 (+ or - 2), and that long term delays (which interrupt memory abilities) seems to have an equal effect on humans and other animals.

I'm not sure about memory and intelligence. I imagine that an adequate memory would at least be necessary, but I'm not sure of whether there are advantages beyond that to intelligence.

rEvolutionist wrote:
Can't it be both? :grin:

If it eases your mind somewhat, I do present a slightly stronger version of my views in threads like this because I think it leads to more interesting discussions and it allows me to assess the consistency of my own views. So whilst personally I'm not exactly convinced that animal and plant learning is the same, here I present it as being pretty similar (at least in some aspects) because I think presenting it as such will help me sum up the pros and cons of the position by looking at the criticisms presented by other people.


I revisited a first year biology text the other day, and one of the major distinctions between plants and animals (in the context of our discussion here) is nerve cells. Animals have them, plants don't. And as far as I could tell, ALL animals have them. I'm guessing it is the ability of nerve cells to form a CNS that make them different from plant cells that carry or transmit chemical signals of some sort. :dunno: The lower animals, like sponges and corals don't have a CNS as such, but a distributed network of nerves in it's place.


Indeed, but the issue is more complex than that. As a broad analogy, this is like saying bats can't fly because they don't have feathers. If we move down the animal kingdom, we reach things like octopi who don't have a CNS in the traditional sense, but instead have a system of nerves that extend throughout its body (which is argued to represent a primitive CNS). However, more simpler creatures like jellyfish and coral have nerve nets that extend throughout its body in a more simple way compared to octopi, but perform similar functions. It's all convergent evolution - finding different solutions to the same problem of how to create an organism that feels pain and can learn.

The more difficult logical leap is in looking at plant "nerves", and assessing whether they are equivalent or similar to animal nerves.

rEvolutionist wrote:
I think the point is that this probability distribution is exactly what occurs with animal learning. Learning is, in essence, the natural selection of behaviors. Wrong behaviors are culled off, and right behaviors are strengthened.


Sure. If learning is involved. But if learning wasn't involved, you would see a tree root making the same mistake on repeated attempts, whereas a rat would start to learn where the dead ends were.


Good point. But would not "making the same mistake" be interpreted as plants continuing to grow roots down paths of a maze that do not result in some kind of reward?

rEvolutionist wrote:
Certainly, there could be a difference there. We'd need to look at whether the reactions of cows, chimps and fish, etc, are a result of some innate behavior or a learnt behavior. This could be an interesting thing to look at in terms of sentience, however, would it make a difference to the suffering of the individual? For example, if we took one person who was innately scared of spiders, and one person who learnt to fear spiders, would there be a difference between the suffering of each person when we bury them in a pit full of spiders?


No, but that's not exactly analogous to what I am talking about. I am wanting to extend to the case where the death of a companion didn't have any innate effects on the animal (well, at least initially until it finally worked out it was dead). For example, the fish in a net watching it's buddy being stabbed to death and wriggling and bleeding all over the place. As they are out of the water, I make the assumption that no chemical or electrical signals will be received. So the fish in the net doesn't suffer anymore than if it hadn't seen its buddy getting dispatched. Compare to a higher animal like ourselves (at least), and we can associate what we see to past events stored in memory and suffer more because of that.


Sure, with humans there is definitely a difference. But with cows and chimps, remove any sounds and smells, and would they react negatively? I'd doubt it.

rEvolutionist wrote:A counterpoint to that is something I was thinking today. I was assuming that Humans could find their way back home from a journey probably better than some animals could. What would those animals be? I don't know (although I bet those fucking useless coral couldn't find their way home if their pathetic lives depended on it :smug: ). But it got me thinking about dogs and their incredible use of scent for tracking. Dogs are renowned for finding their way home from long distances, presumably via scent. So essentially we have two animals that are qualitatively good at retracing their steps, but which use two different "memory systems". We use a visual (and aural) system, whereas dogs use an olfactory system.


Yeah I think this would be the example of a mental ability, and not necessarily intelligence. Some animals are obviously better at navigation than others, especially those that are migratory or nomadic. These abilities might increase their intelligence, or they might have no effect at all on their intelligence.

rEvolutionist wrote:Anyway, the point of that was how it ties back to the fish example. Fish presumably don't use a visual system either (I'm guessing). So while my initial point above asserts that we can suffer more because we can see (and hear) events that can trigger bad memories, dogs and fish would presumably suffer more in a stressful situation in the dark (as long as the fish was underwater, that is) than a deaf human would (or a blind and deaf human in the daytime). So the comparison I was making initially could actually come down to a case of anthropomorphising a valid environment in which to compare between species. I.e., it's no surprise a fish wouldn't do as well at detecting and hypothesising about fear in a human domain, just as much as a human probably wouldn't do as well in the domain of a fish. So maybe it is a bit of a case of horses for courses. Although, this still hinges on a fish's hypothesised ability to store previous occasions of non-innate stress cues in memory for later recalling.


Well I'm not sure about a fish's visual or auditory abilities etc, but I don't think there is any need to doubt their ability to store previous stress cues: http://en.wikipedia.org/wiki/Pain_in_fi ... h_findings

rEvolutionist wrote:As an aside to this, does our large brain allow us to store more memories than a smaller brained animal?


I'm not sure but I don't think it's works like that. Memory is a global process, so it's not like memories are "stored" as such. Also, the advances in our cognitive abilities were mostly a result of our brains getting smaller, in a way, as the folds in our brain improve a number of our abilities.

But I can't really say anything more specific than that. Memory is one of those complicated areas where we know a lot about it, but still don't really understand what's going on..
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Re: Sentience in fish

#88  Postby rEvolutionist » Aug 01, 2011 5:27 am

Just a quick point on one aspect of your above reply...

It seems as if we can make a clear distinction between "intelligence" and "mental abilities". And from what we've discussed, it seems that "mental abilities" might be a more meaningful way of distinguishing between species and their relative strengths and weaknesses. If most animals share a similar level of intelligence, it doesn't have much explanatory power for inter-species differences. I don't want to elevate humans above the rest of the animal kingdom, but I'm searching for an adequate explanation of our success and our abilities to be creative, plan, create and reason. Particularly our ability to philosophise about our place in the world and mentally model our futures.
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Re: Sentience in fish

#89  Postby Dr. Shell » Mar 31, 2014 3:59 pm

The definition of sentient, as in a sentient being, is "responsive to or conscious of sense impressions; aware; finely sensitive in perception or feeling". In other words, does a fish use his senses: touch, sound, vision, and so on, and emotionally and cognitively purposefully react to that input?

I'm trying to determine if this applies to fish (not cetaceans) yet am continually being redirected to animal rights pages. I am an animal rights person, but that's not what I am seeking as far as information with respect to this project. Is a fish a sentient being, by the aforementioned definition?
This is more of a scientifically based, as opposed to a political or emotionally polarized, question.

This string hasn't been addressed in some time. Hopefully someone can write back and answer.
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Re: Sentience in fish

#90  Postby Mr.Samsa » Apr 01, 2014 3:12 am

Dr. Shell wrote:The definition of sentient, as in a sentient being, is "responsive to or conscious of sense impressions; aware; finely sensitive in perception or feeling". In other words, does a fish use his senses: touch, sound, vision, and so on, and emotionally and cognitively purposefully react to that input?

I'm trying to determine if this applies to fish (not cetaceans) yet am continually being redirected to animal rights pages. I am an animal rights person, but that's not what I am seeking as far as information with respect to this project. Is a fish a sentient being, by the aforementioned definition?
This is more of a scientifically based, as opposed to a political or emotionally polarized, question.

This string hasn't been addressed in some time. Hopefully someone can write back and answer.


I think most of the discussion above answers this question and provides some good resources, but the best line of research that will give you the answers you're looking for is pain research. That is, we know that fish not only have a basic reflexive response to pain (i.e. they can escape from pain) but that they are capable of associating cues with the potential for future pain and choosing to avoid the potential for that pain, demonstrating at least a very primitive awareness of pain.

I can't remember if I mention it above but I'm not sure it makes sense to talk of a non-sentient organism that is capable of learning through operant conditioning mechanisms.
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