Fishing for a Solution 2010

Yorkshire Branch Society of Biology Annual Symposium and AGM November 13^th 2010

‘Fishing for a Solution’

The Deep, Hull

(photo by Dot Smith)

A rare phenomenon at this time of year in these parts, a bright blue and gold morning greeted those making an early start for Hull and the low sun and the sparkle from the normally brown Humber were the only traffic hazards.  The gales of the last few days had died down and one could almost see the reflection of the glazed prow of the Deep building in the only slightly disturbed waters of the River Hull. 

This made a good start to a very full day where around 80 members and public (including a large number of school students) listened to a diverse, informative and often entertaining series of talks and were able to take full advantage of the Deep’s exhibitions and aquaria, not least the through - tank tunnel and lift where we were able to make face to face contact as it were with a number of the animals we had heard about.

We were reminded by Paul Bartlett at the outset that we were in the Year of Biodiversity and that the Marine and Coastal Access Act had come into operation with the first Marine Plan from Flamborough to Felixstowe being declared in October with the first 2 Marine Protected Areas coming into force.

Graham Hill, Scientific Officer, demonstrated that The Deep is much more than a public attraction and educational organisation by taking us through the large range of scientific and conservation work that is being undertaken there.  Whilst much of this is related to the care of the animals at the Deep they are also involved in many European and global collaborative conservation projects, notably work with warm water and cold water corals. 

They have pioneered coral fragmentation, reproductive and transportation techniques and The Deep is the European centre for the distribution of coral ‘nubbins’ (paper discs that bear viable coral fragments).  They have developed protocols and techniques for coral sexual reproduction and in vitro fertilization and so far have successfully reared over 150,000 larvae that are distributed to other institutions.  They have also been involved in setting up cryopreservation of coral sperm and a gene bank of corals.  Exotically, gamete collection is done once a year off the coast of Puerto Rico.  Work on sexual reproduction is vital to coral conservation as it maintains genetic diversity at a time when techniques are based on asexual methods. With Natural England, The Deep workers are also involved in basic biological and ecological studies of the Pink Sea Fan that have led to longer survival rates and better husbandry techniques

Various other collaborative studies are being undertaken such as the Lobster Project, and with the Shark Trust – ‘the Great Egg Hunt’ that is an attempt to begin to map shark nurseries around the coast.  This work is especially important because of a decline in shark populations and increased human activity in marine environments such as off shore wind farms.  These are of considerable interest because electrical fields around submerged cables disrupt sharks’ electrosense both in adults and eggs with adverse effects on reproduction.

Veterinary research is another area of activity both in dealing with injuries and disease and in development of new techniques.  Goitre is a problem in sharks and requires management of iodine sources in the water of aquaria whilst the use of modern diagnostic techniques such as MRI scans bring their own problems and solutions. ‘First catch your shark’!

Future projects include collaboration with the Equipe Cousteau on conservation of sharks and rays in the Red Sea where stocks are threatened by tourism and almost unregulated diving.  Alongside such exciting prospects the Deep continues its research, husbandry and educational work whilst providing information and entertainment for a large public audience.

Beginning his very wide ranging presentation Brian Cowx (Director of the University of Hull International Fisheries Institute) told us that marine catches were more or less static, inland capture was still relatively small but there had been a massive growth in aquaculture which now provides about 50% of consumption  worldwide.  A problem with reliability of data is the exclusion of subsistence fishing and angling so calculation of catches may often be underestimated.  Fish is the top protein source for the world ahead of pork and chicken and whilst sea fish are the most important, freshwater fish are also high on the list.  In terms of employment, 47 m world - wide are fishers and around 8% of the world population are dependent on fishing.

There had been massive growth of freshwater fisheries in Asia and a steady growth in Africa (e.g. Lake Victoria), but much less in North America and Europe.  Freshwater fisheries are still the last resort after loss of marine stocks but are still very important with an estimated 47 billion fish caught with 17 billion retained. 

Problems affecting freshwater fisheries include:

Overfishing that can have unexpected effects such as the destruction of sand eel stocks (for aquaculture) causing cormorants to move into inland fisheries

Construction of dams that disrupt seasonal flows and fish migration such as on the Mekong River and the Nile at Lake Victoria

Pollution, though less so in Europe, where in some cases, as in the River Tyne in the UK improvement in water quality has led to the return of significant numbers of fish.  More subtle forms of pollution such as endocrine substances from human medical use have led to all fish at the Thames Barrier becoming female.  In developing countries, pollution arising from human waste, agricultural usage and deforestation are directly or indirectly (such as algal blooms) are still of major importance.

Alien species, deliberately or accidentally reduced can cause problems, though cause and effect are not always easy to discern, but they usually have an effect on the local species.  This is well documented following the introduction of the Nile Perch to the Lake Victoria fishery led to the apparent disappearance of the native cichlid species and led to the explosion of a small fish population – the Daga - as the Nile Perch population was reduced.  The Daga is now caught for aquaculture and it has recently been found that the cichlids (aka Haplochromids) had not been made extinct but had moved out.  The breeding population of piranhas in the power station-warmed waters of the Wigan Canal is less well known.  From whatever cause, 55% of freshwater fish species are either extinct or in decline.

The story of the Mekong River is salutary.  At its best, around 200Kg of fish per net every 20 minutes was normal and overall 2.4 m tons of fish per annum were taken and fed 10 m people.  This was mainly dependent on seasonal water flows and flooding and is now being affected by fishing pressure, flood control, building of new rice fields and alien species which grow readily in the warm water.  The growth in number of hydro-electric dams (“anything but green”) in the Mekong catchment is a major threat to the fishery and there is little local advantage as much of the power is exported.  All of these factors have led to an estimated loss of 60% of the fishery.

This then argues for the need for a management plan, though the situation needs to be looked at as a whole, is very complex and must take into account social and economic considerations.  Such a plan will include restoration, stock enhancement, protected areas and legislation as well as building public awareness, integrated management and bio control.  We need to move to a concept and practice of ecosystem services which bring together the ecological/environmental, the political and the economic factors.  All of this is dependent on good data collection, assessment and interpretation, but scientists need time!

Magnus Johnson (Centre for Marine and Environmental Sciences, Hull University) gave his talk the provocative title “Is Fishing a Sin?” and began by exploring some of the issues affecting fishing and fishing communities, indicating on the way that fishermen often had a poor image “greedy people taking something for nothing”.  Their economic impact is however considerable, with every fisherman at sea sustaining about 7 jobs ashore.  There are however major changes affecting fishing and the environment - and their effective management is not helped by a lag of two years on average between data analysis and action.  Stability depends on a balance between economic, social and environmental factors, but in practice biases come into play.

DEFRA (known in the trade as the Department for the Elimination of Fishing in Rural Areas) is responsible for regulation, but this is not always viewed sympathetically – “Where else do you get prosecuted for doing your job too well?”  There are other pressures on fishermen too, for example the rapid rise in fuel costs, but this is one of many things such as other uses of the sea that affect fish and fishing.  These include undersea cables and pipes, defence uses, wind farms (and ‘electrical pollution’) alongside coastal development and even water from closed mines contaminated with metals such as lead and zinc.  It has been calculated that around 3m fish a year are killed by dissolved lead pollution alone.  None of these influences are easily visible whereas the fishing take is readily observed, though it is true that fishing does have an impact but even here there are well recorded instances of major natural changes in fish populations such as the gadoid outburst which led to massive increases in cod catches and the effects of invasive species such as mitten crabs.  In other words, fish populations vary and may be cyclical, sporadic or irregular which makes such concepts as ‘maximum sustainable yield’ suspect particularly when we have little information on natural rate of mortality in fisheries. 

Current management processes based on regulation and complex regulation at that.  For example net size rules can cause waste as fish species often occurring together such as cod (size of best capture 90 cm) and whiting (30 cm) are caught together.  Another factor is the effect of size of the fish taken: if larger fish are taken there is a regression to similar size which has been shown to increase competition and this destabilizes the population.

All of this indicates that management of fisheries is a much more complex business than is so far practised, but it is clear that legalistic regulation alone is not good enough.  More subtle factors need to be brought into play.  These should engage fishing communities and include

·         A social contract/social capital

·         Social bonds

·         A relationship of trust

·         Reciprocity and exchanges

·         Common rules, norms and sanctions

·         Connectedness in networks and groups

 This would be a far better approach than law and regulation alone as it implies working with fishing communities and offers a chance of better understanding and so more effective observance.

Dr Clare Woulds of the University of Leeds introduced us to the unfamiliar world of sediments at the bottom of the sea and the area of biogeochemistry.  She said that sediments were important in nutrient cycling, carbon deposition, as a climate record and in the getting of fossil fuels.  The habitat factors, food webs and biodiversity of sediments are still not well known.  Sea floor sediments are part of the global carbon cycle but there are relatively small amounts in them and it is not yet known what factors affect this.  Equally, not much is known about the animals, but they are known to have effects on the sediment through burrowing, ingestion, irrigation and oxygenation in burrows - all of which stimulates microbial activity.  Clare has been using isotopic Carbon 13 (non radioactive) to track carbon though the fauna by work in the field and through laboratory systems.

The Arabian Sea has no northerly outlet so circulation is poor, leading to relatively stagnant areas at intermediate levels with poor oxygen levels – an oxygen minimum zone.  Another factor is the regular formation of algal blooms at the surface.  The sediment layers have different chemistry and biology with the low oxygen areas dominated by foraminifera and the lower zones by polychaete worms. 

A cruise along the western Indian coast with an international team using the submersible ‘Shinkai 6500 allowed the investigation of deep water sediments and the presenter to have her first experience of operating in a submersible.  This work revealed a very active environment at 1100m with large animals such as spider crabs and fish varieties.  Clare’s work concentrated on which animals consumed most organic matter, including in situ isotope work. 

Planned future work includes carbon cycling and food web studies at chemosynthetic sites in the Southern Ocean and studies of the effects of hypoxia in Scottish sea lochs.

Outreach work with schools was undertaken as part of a national scheme to replenish the UK’s research base.  This includes getting early career researchers into schools, innovative placement projects, supporting resources where schools are less confident, encouraging school students to enter university and the prospects of research as a career.  Clare’s work in schools has involved addressing assemblies, providing a rock collection, running lunchtime seminars and providing a video diary of her work on the cruise.  She was also involved in the running of ecology and coastal erosion classes and the revision of the Key Stage 3 curriculum.  Student engagement was impressive and outreach work was valuable to the researcher, providing inspiration and reinvigoration, improvement in communication skills and improved confidence and profile personally and for research in general.

The symposium ended with the presentation of the UN Biodiversity film and thanks by the Branch Chair to all the speakers, staff at The Deep and to the branch members, Clive Tiney and Jane Pottas, who had organised the day.

Mike Smith