top of page

SCIENTIFIC PAPERS:

Special Issue on Elasmobranch Behaviour and Cognition:

I was invited to organize a Special Issue on Elasmobranch Behaviour and Cognition for the Journal Behaviour after submitting my account of emotion in the sharks I studied to the journal (scroll down to view). Professor A. Pete Klimley, former student of Arthur A. Myrberg Jr. and world-class shark ethologist, joined me. The Special Issue was inspired by a perceived need to showcase the complexity of the actions displayed by elasmobranchs. With the rise of the shark fin trade at the same time as 90% of traditional fish stocks were depleted by overfishing, they have become the most lucrative fishing targets around the globe while media hype and nature horror shows have raised a barrier to their conservation. Now, with little public protest, those accessible to fishing fleets are declining towards extinction and their status is worse than any other class of vertebrates. Media hype has also facilitated the spread of misinformation about sharks, so that in spite of a wealth of scientific findings to the contrary, the complexity of their mental capacities remains little known. Most people still think of sharks as having a binary mind that tells them only whether or not to bite.


But that is not the case. In response to our Call for Papers relating to the behaviour of elasmobranchs, authors from around the globe responded with articles describing a wide range of compelling behaviour. The Special Issue presents new information about the behaviour of these still little-known aquatic denizens, much of which differs considerably from the familiar actions of the terrestrial species with which we are more familiar.

My own scientific papers are listed below in chronological order:

On the gestation period of the blackfin reef shark, Carcharhinus melanopterus, in waters off Moorea, French Polynesia

ABSTRACT:

Click to download:

Underwater visual and photographic observations, over a four year period, monitored the presence of mating wounds on female Carcharhinus melanopterus. Mating begins in November and continues until the end of March as each female follows her own temporal cycle. Correspondingly, parturition begins in September and continues until January. Each female again mates 1.5 to 2.5 months after parturition, thus completing an annual reproductive cycle. The gestation period is 286 to 305 days, with slight individual differences. All resident sharks under observation followed this pattern. Evidence of reproductive events presented by transient females conformed with the pattern of the residents.

Cite:

Porcher I. F. (2005) On the gestation period of the blackfin reef shark, Carcharhinus melanopter­us, in waters off Moorea, French Polynesia. Mar Bio 146: 1207­1211

Cognition in elasmobranch fishes, a likely possibility

The conference paper on shark cognition I wrote with Arthur Myrberg in 2003

ABSTRACT:

While evidence of cognition in a variety of fish species has been documented, it is widely considered that a class as ancient as the Chondrichthyes is not capable of cognition. We therefore provide a brief summary of the literature concerning learning in elasmobranch fishes, an example of the social organization shown by a colony of captive bonnethead sharks, and supportive observations of free-ranging blackfin reef sharks, all of which suggest cognitive capabilities. We define cognition as a process of intentionally using sequential mental references, as opposed to instinctive reactions to key stimuli. The evidence indicates that elasmobranchs readily learn, possess ecological intelligence, and refer to mental representations to make decisions. Finally, the proof needed to demonstrate cognition, in general, is discussed.

Sadly, Arthur passed away before it could be published--it was a great loss to all humanity, for he was a great man.

Click to download:

I remained in touch with Arthur's colleague, shark ethologist Professor Samuel H. Gruber, founder of Bimini Shark Lab, the American Elasmobranch Society, and The Shark Specialist Group of the World Conservation Union (IUCN). It was he who wrote the foreword to the The Shark Sessions, describing it as 'A jewel of a story.'

 

He told me that because of my work, he and his students had begun to study cognition at the Bimini Shark Lab, which was a great thing, for it will help to improve the image of sharks in peoples' minds. As an introduction to the subject, I was co-author to Tristan Guttrige's review on learning in sharks.

At.home.JPG

The role of learning in shark behaviour

Authors: Tristan Gutridge, Arthur A. Myrberg, Ila France Porcher, David W. Sims, and Jens Krause

ABSTRACT:

The role of learning in behaviour is well known for many animal taxa, including teleost fishes, insects, birds and mammals. However, its importance to sharks in everyday behavioural processes has rarely been considered. Almost 50 years ago the first learning experiments on sharks were conducted; our first section discusses these studies and places them in a framework of associative and non-associative learning. These experiments showed that sharks were capable of different forms of learning, such as operant and classical conditioning and habituation. Sharks could learn associations as rapidly as other vertebrates and also remember training regimes for several months. However, much of this experimental evidence was based on small sample sizes and few shark orders, such as Carcharhiniformes and Orectobliformes, leaving large gaps in our knowledge of the general learning capabilities of other shark orders. We also examine recent research that has tested for, or inferred learning in behavioural processes. This section reveals that sharks, like teleost fishes use learning to improve prey search and capture to potentially navigate and orientate in their home range and recognize conspecifics, heterospecifics and mates. Learning is also discussed in relation to ecotourism and fisheries. Findings indicated that these activities may lead to conditioning of sharks and that considerable effort should go into investigating what impact this could have on the shark species involved. Finally, we discuss the importance of combining laboratory experiments with field studies, the use of new experimental techniques, the role of model species and research priorities for future work.

Cite:

Guttridge, T. L., Myrberg, A. A., Porcher, I. F., Sims, D. W. and Krause, J. (2009) The role of learn­ing in shark behaviour. Fish and Fisheries, 10: 450–469.

Since then, Tristan has found personality differences in lemon sharks, social learning, and other evidence of cognition, while other studies, including lab research, have confirmed that sharks are capable of a variety of cognitive tasks.

Click to download:

lemon.shk.oval.1.png

Response to “A United States shark fin ban would undermine sustainable shark fisheries” D.S. Shiffman & R.E. Hueter, Marine Policy 85 (2017) 138–140

My community of sharks was massacred for the shark fin trade, so I have written often to debunk the pseudo-scientific works of pro-shark fishing 'scientists,' who advocate 'sustainable' shark fishing while sharks approach extinction. The terminology of  "Sustainable Use" proves to be false in this context because it is wholly anthropocentric and denies any intrinsic value to sharks in nature while "Unsustainable" Use is not defined. "Sustainable Use" advocates simply oppose the effective protection of sharks.

pearl.jpg

ABSTRACT:

The paper entitled “A United States shark fin ban would undermine sustainable shark fisheries” (D.S. Shiffman & R.E. Hueter, Marine Policy 85 (2017) 138–140) argues that The Shark Fin Trade Elimination Act of 2017 (HR 1456) and its companion bill in the Senate (S 793), now before Congress in the United States of America, would be counterproductive. We demonstrate that the figures used in support of this claim are inappropriately selected, misinterpreted or incorrect, and that therefore the argument cannot stand. In the face of the extreme depletion of shark numbers globally, the paper fails to give an accurate or objective assessment of the situation.

Cite:

Click to download:

Porcher, I.F., Darvell, B.W. and Cuny, G., 2019. Response to “A United States shark fin ban would undermine sustainable shark fisheries” D.S. Shiffman & R.E. Hueter, Marine Policy 85 (2017) 138-140. Marine Policy, 104, pp. 85-89. https://doi.org/10.1016/j.marpol.2019.02.058

Video about the subject:
Same video in French
Interview in Florida

Shark Fishing and Conservation: Analysis & Synthesis

ABSTRACT:

The growth of the market for shark fin soup, a fashionable, high-end Chinese dish, has resulted in intensive shark fishing across all oceans. At the same time, 90% of teleost fish stocks have become over-exploited, making sharks the most lucrative target. So fisheries that have not previously hunted them are now doing so. As top and middle predators, sharks have high ecological value and poor capacity to withstand fishing mortality, but though their numbers are plummeting, the secretive nature of the fin trade, along with the difficulties of obtaining relevant data, obscure their true status. In consumer countries, shark fin is a luxury item and rich consumers are willing to pay high prices. There is little interest in sustainability or legal trade. Thus market demand will continue to fuel the search for more sharks and those accessible to fishing fleets are increasingly endangered. Current legal protections are not working, as is clearly seen in the case of the shortfin mako shark. Claims that sharks can withstand such targeted, industrial hunting and be sustainably fished under these circumstances are shown to be misguided. In the interests of averting a catastrophic collapse across the planet’s diverse marine, riverine and estuarine ecosystems, sharks and their habitats must be given effective protection. We recommend that all sharks, chimaeras, manta rays, devil rays, and rhino rays be protected from international trade through an immediate CITES Appendix I listing. However, a binding international agreement for protection, not only of sharks, but of threatened ecosystems and the loss of biodiversity in general, is what is most needed.

Cite:

Porcher, I.F.; Darvell, B.W. Shark Fishing vs. Conservation: Analysis and Synthesis. Sustainability 2022, 14, 9548. https://doi.org/10.3390/su14159548

With co-author Dr. Brian W. Darvell, I debunked another piece of fisheries propaganda which is not only blatantly political in nature, but attacks those working for shark conservation:

Lethal flaws found in Shiffman et al. 2021, on science in shark advocacy

ABSTRACT:

Although written in an authoritative style, Shiffman et al.’s paper “The role and value of science in shark conservation advocacy” (2021) contains a number of serious errors which call into question its merit. In particular, it claims that the survey on which it is based shows that conservationists favour bans over sustainable shark fishing more than scientists. But in fact, the survey of scientists cited showed that more scientists favour bans than conservationists. The survey also establishes that conservationists do in fact base their published information on scientific papers, rather than public belief or moral considerations, but the authors focus only on the conservationists’ attitude to the subjects of the two bills now being considered as future legislation in the USA, revealing an essentially political stance.

Click to download:

Commentary on Emotion in Sharks

ABSTRACT

While studying the behaviour of a community of blackfin reef sharks, there was a four month long episode during which the entire company of residents and their visitors showed evidence of feeling a negative emotion towards me. They directed a variety of menacing gestures towards me, and their behaviour escalated until they began battering my kayak on my arrival in their range. Underwater, three would have slammed me personally had I not fought them off. Their behaviour suggested that their cognitive functions are complex, for they held their negative attitude in mind long-term. Two years later, under different conditions, they conveyed, via body language, a positive emotion. Social learning, social buffering, and emotional contagion were also displayed in their actions.

Cite:

Click to download:

Porcher, I. F. (2022). Commentary on emotion in sharks, Behaviour, 159(8-9), 849-866. doi: https://doi.org/10.1163/1568539X-bja10145

friends.oval.png

The following four papers that I authored were published in the Special Edition of  the Journal Behaviour: "Elasmobranch Behaviour and Cognition:"

Ethogram for Blacktip Reef Sharks (Carcharhinus melanopterus)

ABSTRACT

The chondrichthyan lineage diverged from the osteichthyan line around 440 million years ago, resulting in a vast evolutionary gulf between modern elasmobranchs and other vertebrates. Though this has supported the assumption that as an ancient line, elasmobranchs are dangerously stupid, intelligent actions including social interactions have been noted in the field, while laboratory studies have confirmed a variety of cognitive capacities. Yet, due to fear of sharks and the difficulties of observing them in their aquatic environments, few ethological studies have been done, so their natural behaviour remains little known. On noting that the blacktip reef shark (Carcharhinus melanopterus) displayed complex actions during incidental meetings, a long-term ethological study was carried out on the north shore of Mo’orea Island, French Polynesia. During the 6.5 years involved, new behaviours continued to present. The 35 context-specific actions identified as comprising the behavioural repertoire of C. melanopterus are described.

Cite:

Click to download:

Porcher, I. F. (2023). Ethogram for blacktip reef sharks (Carcharhinus melanopterus). Behaviour, 1(aop), 1-38.

Shark Evacuation from Mo’orea Island in 2002

ABSTRACT

Reef sharks, including blackfins (Carcharhinus melanopterus) reside in the lagoons and on the outer slopes of the barrier reefs of Mo’orea Island, French Polynesia. In general the lagoons are shallow enough to permit underwater observation, while dive clubs hold shark dives at different sites in the lagoons and in the ocean. Thus, the presence of blackfin sharks especially, and other species at times, is confirmed daily. Between about 21 July and 2 August 2002, all blackfin reef sharks under observation, and possibly some of the other species, left their lagoon and ocean ranges and disappeared from human view, a unique evacuation for which no explanation was found. The event suggests an unknown pattern or influence at work which was perceived by sharks, but was not apparent to those investigating.

Cite:

Click to download:

Porcher, I. F. (2022). Commentary on emotion in sharks, Behaviour, 159(8-9), 849-866. doi: https://doi.org/10.1163/1568539X-bja10145

A review of the behaviours of the Chondrichthyes: a multi-species ethogram for the chimaeras, sharks, and rays

Authors: A. Peter Klimley, Ila F. Porcher, Eric E.G. Clua, and Harold L. Pratt Jr.

ABSTRACT

In this review of the behavioural patterns of chondrichthyan fishes, we have strived to produce a comprehensive catalogue of events and states and develop standardized terminology. Hence, actions that are slightly different, will be pooled under inclusive titles. Those used by different investigators are included in quotations within the textual descriptions of the motor patterns. This standardized ethogram will ideally lead to an increase in inter-observer reliability, giving researchers more confidence when reading colleagues’ papers that report behaviours that appear similar to theirs despite being described for different species. The descriptions are presented under the following categories: (1) maintenance (2) courtship (3) filter feeding (4) scavenging (5) predation (6) sociality (7) aggression and (8) defence. The many actions are illustrated by line drawings and photographs in composite figures with an attempt to provide an example of each action for a chimaera, shark, and ray. The diversity of patterns is evident from this ethogram, consistent with observation that the brain-to-body mass ratios of cartilaginous fishes are greater than a third of the bird species and greater than those for some mammalian species. The major impetus for assembling this ethogram is to demonstrate the diversity of behaviours exhibited by members of the Chondrichthyes and to dispel the apocryphal belief that members of this taxon are ‘simple feeding machines’.

Cite:

Klimley, A. P., Porcher, I. F., Clua, E. E., & Pratt, H. L., Jr. (2023). A review of the behaviours of the Chondrichthyes: a multi-species ethogram for the chimaeras, sharks, and rays. Behaviour, 160(11-14), 967-1080. https://doi.org/10.1163/1568539X-bja10214

Commentary on: dominance and subordination in the smooth dogfish, Mustelus canis (Allee & Dickenson, 1954)

ABSTRACT

In, 1954, Warder C. Allee and Joshua C. Dickinson decided to establish that “dominance- subordination” hierarchies are present in the Chondrichthyan phylogenetic line. To do so, they confined sixteen fished smooth dogfish (Mustelus canis) in tanks and observed their behaviour. They found neither competition over food, in spite of starving the animals for up to six days at times, nor any clear example of aggression, though it is through aggressive actions that such hierarchies are, by definition, established. They therefore used collision avoidance to support their hypothesis that the sharks had established a rigid size-dependent dominance-subordinate hierarchy, and claimed to have established that such hierarchies are present in Chondrichthyans. However, ethological studies since then have not identified the hierarchies in elasmobranchs that this study claims to be present, but they have found that smaller sharks tend to avoid colliding with larger individuals, which is the simplest explanation for their observations.

Cite:

Click to download:

Porcher, I. F. (2023). Commentary on: dominance and subordination in the smooth dogfish, Mustelus canis (Allee & Dickenson, 1954). Behaviour, 160(11-14), 1137-1151. https://doi.org/10.1163/1568539X-bja10226

The Elephant in the Garden

Animal Sentience Thread:
Colin A. Chapman and Michael A. Huffman, "Why do we want to think humans are different?"

ABSTRACT

The other commentators on Chapman & Huffman (2018) have pointed out in different ways that despite our biological nature, there is a widespread tendency for humans to believe that we are not only superior to animals, but that we are not animals at all. Alongside our denial of animal sentience and cognition, this has resulted in the denial of our own instinctive natures. It is this denial that is our error, for it is only by understanding our true natural heritage that we can begin to change the runaway path we are on.

Cite:

Click to download:

Porcher, Ila France (2023) The elephant in the garden. Animal Sentience 23(55)

art.jpg

The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.  ~ Albert Einstein ~

bottom of page