Seafood accounts for a sizable portion of the protein that sustains much of the human population of our planet. Not only is this resource a necessity for many people, but provides what may be seen as a huge "recreational" food source for much of the industrialized world as well as a source of livelihood for millions of people.
It is therefore in the best interest of all involved, be they consumer, fisherman or environmentalist, to keep the natural stocks of the species that make up this important market healthy for current and future generations. And given our population of 6.5 billion, this can only be done with smart and consistent regulation of the fisheries on a global level. This of course assumes we are dealing with lawmakers and world leaders who actually believe in governing through science and common sense rather than through an ideological and corporatist world-view.
And that’s the rub. But I believe the lobster fishery of the North Atlantic can provide a real-life example of how this can be accomplished. Although treated as an inedible food source in the eighteenth and early nineteenth centuries, suitable only for livestock and slaves, by the late eighteen hundreds this crustacean became a highly sought-after delicacy. So much so that by the turn of the century they were thought to be in danger of extinction.
One of the earliest conservation measures in this country was taken by the Federal Committee to Study the Lobster and Soft-shell Clam Fisheries, which imposed unprecedented limitations on the size and quotas of the lobster harvest. These actions reversed the decline of Atlantic lobster (Homarus americanus) populations and stabilized them for over a hundred years. Today, in spite of being one of the most highly prized marine resource, their numbers are at near record levels, even with roughly 80 million pounds being landed each year. This has been accomplished due to extensive scientific study into the life cycle and biology of these animals and the cooperation of regulatory agencies and the lobster fishermen themselves.
Growth Overfishing
The term "overfishing" is thrown around quite a bit in conservation circles, but it should be stressed that there are two specific types of overfishing that affect a species’ population. One is growth overfishing, which occurs when in a heavily fished species the individuals are not allowed to grow to their full potential. This is clearly seen in the case of the Atlantic lobster. In the early days of lobstering it wasn’t unusual to find lobsters that weighed thirty, forty or even fifty pounds. This is absolutely unheard of today and it is estimated that up to 80% of all lobsters are caught within a year of reaching their minimum legal size (roughly 1 1/2 pounds). In fact, the largest lobster on record was trapped in the 1920’s and even though the population has been relatively stable, no lobster even close to that one’s weight of 52 pounds has been seen since.
While growth overfishing doesn’t threaten the population as a whole, it does limit the potential of the resource since it limits the number of times a female can reproduce (by decades) as well as the total number of young any one individual can produce. A ten pounder can produce many more eggs than a first year breeder. Growth overfishing can be offset, and has in this fishery’s case, in several ways. One is to limit the size that a lobster can be legally harvested. This guarantees that all adults at least get some chance to reproduce. Another strategy is to protect a certain number of proven breeders. For example, the taking of egg-bearing females, regardless of size, is strictly forbidden, and may result in very hefty fines and the revoking of a fisherman’s license.
Another way this is done is by V-notching large females. This involves a regulatory agency instructing spotters to cut v-shaped notches on the tails of these lobsters. It is then illegal for a fisherman to keep any v-notched animals he finds, whether they are bearing eggs or not. One problem, of course, is that lobsters regenerate damaged parts of their exoskeletons each time they molt, so v-notched individuals must be re-marked each time they are caught.
Recruitment Overfishing
A more damaging type of overfishing is known as recruitment overfishing. This occurs when the adults of a species are so depleted that they are unable to replenish themselves and the result, like we see with stocks of cod, sturgeon and bluefin tuna, is a near total population collapse that could eventually lead to extinction.
The solution to recruitment overfishing is to not just limit the size of the animals harvested, but the numbers that can be taken each year. In other words, quotas. In the lobster fishery this is done mainly by limiting the number of traps issued to each person, the numbers that can be taken by draggers and by banning certain types of fishing such as night harvesting (when the lobsters are most active and easily captured). Protecting a fish from recruitment overfishing can only be effective when extensive scientific study of the species is completed to assess what the population size is, how fast they reproduce and how well they recover from being commercially fished. Lobsters are one of the few marine animals that we know these factors in detail.
Preventing recruitment overfishing saves the species and can allow the fishery to continue. However, preventing growth overfishing should be a very high priorty for fishermen and conservation agencies alike since it not only protects the species but can also actually increase the numbers of fish available for future harvests. The lobster industry seems to realize this, I’m not sure why others don’t seem to as well.
Other diaries in this series can be found here.