‘Playing with fish’
Date Released: Wed, 12 October 2011 16:00 +0200
Professor Warwick Sauer gave an informative and entertaining inaugural lecture to a packed Eden Grove Blue Lecture Theatre.
Prof Sauer who is the Head of Department of the Department of Ichthyology and Fisheries Science said he was gratified to have the opportunity to look back on twenty years of “playing with fish”, and his involvement with research and community engagement in the Eastern Cape.
Early in his career, he became fascinated with the local squid or chokka which, until thirty years ago, were regarded as fit for use as bait only.
This changed after PW Botha’s ‘Rubicon’ speech of 1985, which led to a fast-dropping exchange rate and prompted a search for home-grown options. The process was speeded up by a Portuguese native who realised that the local chokka were similar to an expensive delicacy in Portugal.
The South African chokka fishing industry was born, and Prof Sauer was among the first to get involved in this new, and as yet unlicensed and unregulated, industry.
In the later 1980s regulation of the industry began, and larger boats with on-board freezing and packing facilities began to be the norm. With this escalation came concerns about sustainability, and a research programme was initiated, in which Prof Sauer became heavily involved.
The researchers were looking to find proof that the squid were spawning in sufficient numbers, and Prof Sauer was, he said, thrilled to have been the first person to witness what has been called the “dance of desire” which is the breeding process of the squid.
It is a complicated undertaking; the male consort in a breeding pair has a special ‘arm’ which is inserted into the female, reaching to the oviduct where it deposits sperm.
However, there are other males too, called ‘sneaker males’ who gain their name by darting in and depositing their own sperm on the body of the female.
A research project to establish how this unusual arrangement pans out in the genetics of the squid offspring was undertaken, and it was found that at least four different males can be seen to have fathered offspring contained in one egg string. As ‘sneakers’ and consorts have different sperm types, further questions were raised, including that of whether the female has a choice as to which sperm she utilises, and research into these animals is still ongoing.
In the search to establish sustainability, Prof Sauer and his research team mapped the ocean using a small aircraft and discovered that squid spawning sites are predominantly clustered from Plettenberg Bay to Port Alfred. By working with local fisherman, and placing sensitive instruments on the sea floor, a monitoring process was begun.
The need to tag squid arose, in order to establish what patterns, if any, could be deduced from re-catches, which saw the researchers offering R500 per tag recovered to any fisherman who could inform them where the squid had been caught. This method established that the squid were moving from spawning site to spawning site.
However, a Canadian invention took the research to a new level. Using radio acoustic positioning telemetry (RAPT), with transmitters positioned in the squids’ mantles using hypodermic needles to secure the transmitters, researchers were able to monitor squid for a seven day span, and finally establish that the breeding patterns of the squid are not disrupted by fishing.
The research also uncovered a wealth of seemingly intelligent behaviour. The squid has the largest brain of any invertebrate, and they ‘think’ themselves invisible, or into different colours and patterns. This appears to be a means of communication, a language of colours.
Prof Sauer has had the opportunity to compare squid species from around the world, including such far-flung locations as Japan, Madagascar and California, and has therefore been able to produce a world-wide comprehensive study of spawning squid. The last truly incredible forms of life are likely, he says, to be found in the deep oceans. The challenge now is how to stimulate young minds into the exciting world of marine science.
He concluded his lecture with a stern warning on the plight in which the marine environment finds itself. World Fisheries are in crisis. A world-wide allocations dilemma exists, with unscrupulous overfishing taking place in Africa and elsewhere.
A fishery is a biological, economic, legal and social system, aspects of which are often ignored. Resource management practitioners seldom change their policies in response to past failures, and more research is desperately needed, especially considering human population is increasing at a rate of 1.8% per annum.
Increased population growth and increased per capita consumption of natural resources, he told the audience in closing, are the major factors most likely to result in breakdown of both normal ecosystem function and social structure, and the taboo placed on discussing and addressing these issues by political, economic and religious forces needs to end.
By Jeannie McKeown
Photo by Sophie Smith