Black Seabass   Photo Credit:  Octavio Aburto 

Sea Bass

CMBC commentary on sea bass caught in La Jolla Cove.

(San Diego Union Tribune  26 April 2006)

Why should we care about the spearing of one sea bass in a small reserve in La Jolla Cove?

As residents of a coastal city such as San Diego, we all depend upon the healthy functioning of our nearshore marine environments- for food, recreation, coastal stabilization, water quality control, and various other goods and services. A healthy environment in turn, depends upon the interactions of local marine species. But what happens if the link between the goods and services provided by the ecosystem and the species which comprise that ecosystem is broken? Through overfishing and various other human activities we are systematically breaking down marine ecosystems so that they can no longer function as they did in the past. The loss of one sea bass merits attention not only because we mourn the loss of a very old, very big fish, but also because we are reminded that this incident is a local example of a global phenomenon- and this phenomenon has immediate, direct consequences for our community.

This particular case was especially harmful for a number of reasons. First, it involved spearing a protected species; second, the fish was speared within a protected marine reserve; third, the fish speared was particularly large, and larger individuals contribute a disproportionately high amount of offspring to the next generation of the species; fourth, this species was one of only five (now four) large black sea bass in the region (compounding the impact of the previous point). Below we will address these issues and discuss the relevance on both the local and global scale.

Fishing is by far the oldest and perhaps the greatest human disturbance on marine ecosystems. After centuries of intensive hunting, populations of large marine species are at historic lows. Declines in species such as abalone, lobster, and especially fish were noted in the La Jolla cove region as early as the 1940s. Large marine organisms, such as the sea bass, are particularly susceptible to overfishing. They grow slowly, have a late age at maturity, and do not produce enough offspring to offset the pressure applied by many a spear, reel, or net. For this reason, particular species are protected. Protection of species have one goal in mind: to allow for increased numbers of adult fish to survive and reproduce in order to increase local and global population size of the species. For many marine species, these regulations are the only respite to an unceasing increase of fishing pressure. In the face of advanced technology and improved fishing gear, these species have simply run out of places to hide.

Marine protected areas, like the San Diego La Jolla Ecological Reserve, where the sea bass was poached, are one type of management strategy aimed at reversing the declines in local species populations. The reserve in La Jolla was established in 1971 as a no-take reserve to allow for local populations to increase to former abundances. Reserves such as this one serve as a means for ecosystems to recover their complete suite of species abundance and diversity. The ultimate goal of such reserves is not simply to provide small relics of healthy ecosystems, but to serve as a seed bank to support rehabilitation of surrounding habitats. And often, reserves show positive trends in the direction of this goal.

This is the case in La Jolla. After all, why did the spearfishermen choose to hunt near and within the reserve? Simply put: outside the reserves, there are almost no big fish anywhere else in San Diego. In fact, it is increasingly difficult to find any large fish (especially ones weighing in at over 170 lbs) in coastal waters across the globe. But they can be found inside reserves and near reserve boundaries, where protection from intensive fishing have allowed a few individuals to slowly increase in size and number over time. Unfortunately, this success is also the Achilles heel of the reserve, as they become targets for those who remain ignorant of the protection or defiant in the face of it. Either way, the spearing of this giant sea bass is the equivalent to killing a bison, bear or wolf in Yellowstone National Park, or like cutting down a sequoia tree in the Sequoia National Park. It is illegal and illegal for a reason. Just as we needed to set aside wild places on land where ecosystems could function intact and provide resources to exploited environments, so too do we need to set aside wild places in the sea. And we must enforce these regulations.

The loss of large, rare individuals is of particular concern as the impacts are disproportionately high for the local population. One fully-grown adult sea bass produces from ten to a thousand times as many offspring as an individual half of its size. The loss of this one sea bass therefore has a significantly negative impact on the local population of this species.

Species declines have occurred across the animal kingdom, from the swimming fish to the sedentary mollusk. With the decline of these species, we lose a valuable food resource. But the impacts do not end here. As these species are intimately connected to others in the web of life, declines in one result in changes in others. Such effects ripple throughout the kelp forest and have significant consequences for the stability and health of the entire ecosystem. These ecosystems provide food, medical resources, coastal stabilization, and a suite of other goods and services to our societies. So, no matter where your priorities lie, the loss of this sea bass reflects upon an issue that is of great importance to us all- the declining health of our oceans. As informed citizens of this coastal city, we must reflect upon the loss of this fish as a reminder that there is much at stake in the global oceans. And our choices of tomorrow, in terms of our recreation, diet, lifestyle, and health, depend upon our consumption patterns, our actions, and our voices of today.

For more information on the impact of overfishing and the effect on marine ecosystems, see:

Casey JM, Myers RA (1998) Near extinction of large, widely distributed fish. Science 281: 690-692

Dayton PK, Tegner MJ, Edwards PB, Riser KL (1998) Sliding baselines, ghosts, and reduced expectations in kelp forest communities. Ecological Applications 8: 309-322

J, Jeremy B. C., Kirby M, Berger W, Bjorndal KA, Botsford L, Bourque BJ, Bradbury RH, Cooke RG, Erlandson J, Estes JA, Hughes TP, Kidwell S, Lange C, Lenihan H, Pandolfi JM, Peterson C, Steneck R, Tegner MJ, Warner RR (2001) Historical Overfishing and the Collapse of Coastal Ecosystems. Science 293: 629-638

McArdle, D. 2002. California Marine Protected Areas. California Sea Grant, Publication T-050.

Myers RA, Worm B (2003) Rapid worldwide depletion of predatory fish communities. Nature 423: 280-283

Bascompte, J. Melin, C., and Sala, E. 2005. Interaction strength combinations and the overfishing of a marine food web. PNAS 102(15):5443-5447.

www.shiftingbaselines.org