Severe over fishing has happened partly because of a belief that the oceans’ resources are inexhaustible. Now we know that the ability of the ocean to produce food fish is limited by the amount of plankton produced and that fishing is at or beyond the sustainable limit. We also know that ecosystems are complex and poorly understood with many interactions. We recognize that humans are major players in marine ecosystems and that our actions on land and at sea affect marine ecosystems and ecosystems affect us
Back to the BIG question. How do we make sure that today’s fisheries do not lead to undesirable changes for future generations? The answers are not simple and involve laws, treaties, regulations, enforcement. These are all based on science, local and traditional knowledge and of course politics. Sustainable management is really all about controlling human activities and impact.
We need to manage for the future and be more cautious because there are so many unknowns. Sustaining marine fisheries means fishing less, reducing fishing pressure and fishing intensity. This may mean short term pain for long term gain while fish populations rebuild, but most fishery systems are slowly reversible. Long lived, slowly reproducing species and species whose critical spawning or nursery habitat has been damaged will respond more slowly.
Rules on net mesh size, net size, boat size, gear type, when and where and how many boats all help reduce fishing mortality and by-catch. Historically fishing was open to all and as competitors for a share in the fishery, the goal was to catch a bigger share quickly with no incentive in conserving for the future. This has led to too many boats with too much ability to catch fish (over capacity). Increasing incentive in conserving for the future by assigning rights is one way to avoid this “tragedy of the commons”. Rights can be assigned to communities, individuals, corporations or geographical areas.
Adaptive management is an experimental approach where management actions are put into place like an experiment. Hypotheses are tested, data is collected and changes can be made to actions as hypotheses are either accepted or rejected. Marine Protected Areas can be managed adaptively and provide valuable information. Other regulations such as by-catch reducer gear can also be managed adaptively if carefully controlled to help us gain valuable information on sustainability. By catch and discards must be counted in management plans as part of the overall ecosystem impact.
Collecting long term data and monitoring marine ecosystems are important for detecting trends, assessing fish populations and ecosystems. Data collected can be used in models to help make predictions. Modelling approaches to fisheries management that are based on ecosystem interactions are promising management tools but depend entirely on reliable data. Modelling such a chaotic complex system as the ocean has so far proved difficult but at least it can help us avoid the “killer spike” that has collapsed many floundering fisheries.
Whatever management system is used it is critically important to involve the “users” and communities in the decision-making. After all they are the ones who can make it work and who are most affected.

 

Science for Sustainable Sea Urchin Fisheries in BC

Graduate Student, Michael T. Nishizaki,
University of Northern British Columbia and The Bamfield Marine Sciences Centre

What is the fishery for sea urchins all about?
Over the past two decades, sea urchins from the West Coast of British Columbia have been harvested for export to Japan where the gonads are used for sushi. These spiny bottom-dwellers are important grazers of the kelp forest and can live up to 100 years.

What questions are you working on?
Juvenile sea urchin recruitment is highly variable and poorly understood. What divers have observed since the late 1970’s is that juvenile red urchins are found almost always, under the spines of groups of adults. Some people have called for regulations protecting shallow groups of adult urchins as nursery habitats for juveniles. However, imposing these types of restrictions would be difficult without knowing why juveniles shelter under adults.

How do you do your research?
With the support of the Bamfield Marine Sciences Centre, we are combining laboratory experiments with field surveys to understand juvenile urchin ecology. In the lab, we have observed that juveniles shelter under adults when water motion is high or when predators are present. Growth experiments also show that sheltering juveniles are subject to competition with adults and often have limited access to food resources such as kelp. In the field, underwater divers have conducted subtidal surveys searching for juveniles by hand and using an underwater vacuum. So far these field surveys appear to support the conclusions of our laboratory experiments.

Are there practical applications for the fishery?
This study, has improved our understanding of juvenile urchin ecology and has several applications. For commercial divers, we have identified several reasons why adult sheltering benefits juvenile growth and reduces mortality. Apart from harvesting, the topic of “outplanting” laboratory-raised juveniles in the field to boost wild stocks has been proposed. Our work has helped identify what type of biological and physical microhabitats one should look for when outplanting these vulnerable juveniles. Results of this project have been submitted both to the government and urchin harvesters in BC and are published in Echinoderms 2000 (Swets & Zeitlinger Publishers).

One of the most important skills a scientist can have is the skill of observation. Develop this skill by observing and drawing marine life. Take pen and paper and go to an aquarium, beach or library. Look for marine life and draw it. Include as much detail as possible about what you observe.

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