You are claiming that fish have the ability to reason, which I have difficulty believing. Their patterns of behaviour are based on instinct. Do you have any research or published findings to support your hypothesis of learning capacity in fish? or of the non-recovery of East Coast Cod populations? If you do, I would be interested in seeing it. Double A, I have always respected your opinion. I have my views, but always prepared to change them with a preponderance of evidence. :cool
Thanks back to you also FA. I appreciate your posts and respectful responses as well. See below:
---------------------------------------------------------------------------------------------------------
http://www.howfishbehave.ca/pdf/Social intelligence.pdf
Social intelligence in fishes. Stéphan G. Reebs. Université de Moncton, Canada. 2010
------------------------------------------------------------------------------------------------------------
<iframe width="640" height="360" src="https://www.youtube.com/embed/Xjt6QJSo4qs?feature=player_detailpage" frameborder="0" allowfullscreen></iframe>
------------------------------------------------------------------------------------------------------
http://www.researchgate.net/profile...and_ethics/links/0c96053b488f9c558a000000.pdf
Anim Cogn
DOI 10.1007/s10071-014-0761-0
Fish intelligence, sentience and ethics. Culum Brown
Received: 13 November 2013 / Revised: 7 May 2014 / Accepted: 19 May 2014
Springer-Verlag Berlin Heidelberg 2014
Abstract: Fish are one of the most highly utilised vertebrate taxa by humans; they are harvested from wild stocks as part of global fishing industries, grown under intensive aquaculture conditions, are the most common pet and are widely used for scientific research. But fish are seldom afforded the same level of compassion or welfare as warm-blooded vertebrates. Part of the problem is the large gap between people’s perception of fish intelligence and the scientific reality. This is an important issue because public perception guides government policy. The perception of an animal’s intelligence often drives our decision whether or not to include them in our moral circle. From a welfare perspective, most researchers would suggest that if an animal is sentient, then it can most likely suffer and should therefore be offered some form of formal protection. There has been a debate about fish welfare for decades which centres on the question of whether they are sentient or conscious. The implications for affording the same level of protection to fish as other vertebrates are great, not least because of fishing-related industries. Here, I review the current state of knowledge of fish cognition starting with their sensory perception and moving on to cognition. The review reveals that fish perception and cognitive abilities often match or exceed other vertebrates. A review of the evidence for pain perception strongly suggests that fish experience pain in a manner similar to the rest of the vertebrates. Although scientists cannot provide a definitive answer on the level of consciousness for any nonhuman vertebrate, the extensive evidence of fish behavioural and cognitive sophistication and pain perception suggests that best practice would be to lend fish the same level of protection as any other vertebrate.
"
Conclusions
Fish have very good memories, live in complex social communities where they keep track of individuals and can learn from one another; a process that leads to the development of stable cultural traditions. They recognise themselves and others. They cooperate with one another and show signs of Machiavellian intelligence such as cooperation and reconciliation. They build complex structures, are capable of tool use and use the same methods for keeping track of quantities as we do. For the most part, their primary senses are just as good, and in many cases better, than our own. When comparing their behaviour to primates, one finds very few differences with the exception, perhaps, of the ability for imitation (Bshary et al. 2002). One must conclude, therefore, that the level of cognitive complexity displayed by fishes is on a par with most other vertebrates, and that if any animals are sentient then one must conclude that fish are too. While their brain evolutionary and developmental trajectory differs from other vertebrates, it is evident that there are many analogous structures that perform similar functions. This body of evidence strongly suggests that they are sentient and the evidence that they are capably of feeling pain in a manner similar to humans is gradually mounting. I submit that there are compelling reasons to include fish in our ‘‘moral circle’’ and afford them the protection they deserve."
---------------------------------------------------------------------------------------------------------
http://icesjms.oxfordjournals.org/content/61/7/1144.full
Depensation, probability of fertilization, and the mating system of Atlantic cod (Gadus morhua L.)
Sherrylynn Rowea,*, Jeffrey A. Hutchingsa, Dorte Bekkevoldb and Ana Rakitinc
*Correspondence to S. Rowe. e-mail:
sherrylynn.Rowe@Dal.ca.
Abstract
Atlantic cod (Gadus morhua L.) have been severely overexploited and are currently at historic population lows, having declined 90% in the North Sea and 99% off northeast Newfoundland in recent decades. Slow rates of recovery and continuing declines may be attributable to depensation, defined as a reduction in per capita growth rate concomitant with reduced population size. Several potential causes of depensation relate to low mating success and consequent reduced production of offspring. We explore the empirical basis of one of these in Atlantic cod using egg fertilization and male abundance data obtained from 21 experimental populations generated by three independent research programmes. We find support for the hypotheses that (a) fertilization rate declines with abundance and (b) variance in fertilization rate increases as population size declines. The former identifies one potential mechanism underlying depensation in Atlantic cod. The latter has negative genetic consequences for effective population size (Ne), resulting in a decline in the ratio of Ne to census population size (Ne/Nc) with declining abundance. Our results may have general implications for the conservation biology of broadcast-spawning marine fish, particularly those with mating systems similar to that of Atlantic cod.
-----------------------------------------------------------------------------------------------------------------
http://www.researchgate.net/profile...s_morhua_)/links/00b7d529dd176be8c6000000.pdf
Abstract: Changes to life history traits are often concomitant with prolonged periods of exploitation. In the Northwest Atlantic, 30- to 40-year declines of more than 90% of Atlantic cod (Gadus morhua) have been associated with significant reductions in age and length at maturity, changes most parsimoniously explained as genetic responses to fishing. Increased survival costs of reproduction associated with earlier maturity, resulting in higher natural mortality and shorter life span, negatively affect population growth rate and rate of recovery. Coupled with lower hatching rate among first-time spawners and smaller size at maturity, a modest reduction in age from 6 to 4 years can reduce annual population growth in Atlantic cod by 25%–30%, based on the output of a stochastic, age-structured life history model. Earlier maturity more than doubles the probability of negative population growth every generation. These results underscore the potential for fishing-induced changes to life history traits alone to generate slow or negligible recovery in marine fishes, exacerbating negative impacts on population growth resulting from ecosystem-level alterations to interspecific competition and predation.
----------------------------------------------------------------------------------------------------------
Image below from: Cod: The Ecological History of the North Atlantic Fisheries By George A. Rose
https://books.google.ca/books?id=tD...onepage&q=cod stocks breeding females&f=false