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Session Abstracts Saturday, March 7, 1998
Welcome
Plenary Session
MAY THE CIRCLE BE UNBROKEN: PROTECTING THE MONTEREY BAY THROUGH INTEGRATED CUMULATIVE IMPACTS MANAGEMENT BALANCING VESSEL TRAFFIC AND THE MONTEREY BAY NATIONAL MARINE SANCTUARY Chip Sharpe, Commander, US Coast Guard; STATUS OF FISHERIES IN THE MONTEREY BAY NATIONAL MARINE SANCTUARY Richard M. Starr Marine Advisor UC Sea Grant Extension Program Fisheries in central California are part of this region's rich cultural history. Almost 200 species are caught in commercial and recreational fisheries in the MBNMS. Commercial fishers in the Monterey Bay National Marine Sanctuary use five primary types of fishing gear - pots and traps, trawl nets, hook-and-line gear, purse seines, and gill nets. In recent years, more than 80% of the commercial fish landings in the Sanctuary were comprised of squid, rockfishes, Dover sole, anchovy, mackerel, sardine, sablefish, albacore, and salmon. Salmon and rockfishes are the species most sought after by recreational fishers. The status of commercial and recreational fisheries in the MBNMS, and by extension the status or health of fish populations, is influenced by numerous social, economic, environmental, and biological variables. Large scale environmental changes alter the numbers of fishes in the sea on a cyclical basis. Fisheries reduce populations of marine fishes, especially relative to preharvest levels. Increased human use of the coastal zone also negatively affects fish populations by degrading spawning or rearing habitats. Fishery managers use both fishery catch data and scientific research data to estimate the population size of a managed species. In the past 15 years, reported catches have increased or been stable for about 17% of the species frequently harvested in this region. Reported catches declined for about 10% of the frequently harvested species. Catches of other species are either unknown or highly variable. Population models indicate that some species groups such as flatfishes are experiencing increasing populations, whereas other species groups such as rockfishes are experiencing greatly declining populations. The increasing population size of some species and the declining abundances of other species creates numerous fishery management challenges. Research Symposium EXOTIC SPECIES IN CALIFORNIA'S COASTAL WATERS Andy CohenSan Francisco Estuary Institute Exotic organisms may constitute the largest single threat to the biological diversity of the world's coastal regions. Exotic organisms have invaded many of California's coastal habitats, including beaches and dune areas, marshes, mudflats and open waters, in fresh, brackish and salt-water environments. These invasions have been most intensively studied in the San Francisco Bay/Delta Estuary, which hosts over 230 exotic species including protozoans, plants and animals. More significant than the sheer number of exotic species is their dominance in some habitats, accounting for 40% to 100% of the common species at many sites and sometimes over 90% of the biomass. Recent analysis shows that the rate of invasion has been dramatically increasing in recent decades, from an average rate of less than one new species a year before 1960, to nearly four new species a year since 1960. While estuaries, bays and harbors have been the most affected areas, exotic species are beginning to threaten marine habitats on the open coast. A New Zealand sea slug, arriving in San Francisco Bay by 1992, spread both to other central California bays where it has become very abundant, and to sandy bottoms on the outer coast where it is now commonly collected all the way to southern California. A South African sabellid worm that parasitizes abalone, and threatens many other types of marine snails in rocky habitats, has been released and continues to be released by abalone farmers, and appears to be established in at least one site. The scale of international trade and shipping and of aquaculture are both expected to rapidly expand in the coming decades. If left unregulated, these activities will accidentally transport an ever-growing number and diversity of marine organisms (including parasites and diseases of fish and shellfish) resulting in a further acceleration of the rate of invasion. The adoption and implementation of a few common-sense measures, as has been urged by marine scientists, could substantially reduce this threat. TOXIC CHEMICALS AND AQUATIC ORGANISMS: AN OVERVIEW OF RECENT STUDIES AROUND MONTEREY BAY John W. Hunt University of California, Santa Cruz A variety of human activities have resulted in past and current releases of toxic chemicals into aquatic environments in and around Monterey Bay. The Bay itself is well mixed, and concentrations of toxic chemicals are generally low in Bay waters, sediments and organisms. Santa Cruz, Moss Landing, and Monterey Harbors have each received inputs of various industrial, agricultural, and commercially available compounds, which have accumulated in harbor sediments. Watersheds draining to the Bay receive household, agricultural and urban storm water runoff containing toxic concentrations of associated chemicals. A number of scientific studies have investigated the sources, transport, and biological effects of trace metals, pesticides, hydrocarbons, and PCBs in the area. Many of these studies have focused on efforts by farmers and resource managers to limit chemical inflows through improved retention of contaminated soil and storm water. Projects have been sponsored by a number of agencies involving scientists from many local institutions. These studies will be briefly reviewed to give an overview of the current state of our knowledge concerning anthropogenic chemicals and their effects on the fish, plants and invertebrates of the Monterey Bay system. VISITOR IMPACT ON ROCKY SHORES: ARE MARINE PROTECTED AREAS REALLY PROTECTED? Steve Murray Department of Biological Science, California State University, Fullerton In Southern California and elsewhere, unlawful human collecting and visitor foot traffic are damaging rocky intertidal populations even in Marine Protected Areas (MPAs). Here, we document the intensities of human visitation and unlawful collecting on rocky shores in long-established and signed MPAs located in urban Southern California. We also report results of experiments revealing that visitor foot traffic can significantly damage rockweed and mussel populations. Based on our observations and results from these and other studies, we hypothesize that as configured and managed MPAs may not be protecting shore populations from visitor damage. Even in MPAs, certain populations may be suffering reductions in abundance and experiencing important shifts in population structure, including lower frequencies of the larger-sized individuals that yield the greatest reproductive output. We conclude that existing MPA regulations and management are ineffective in Southern California and elsewhere and are in need of re-evaluation. (Supported by NOAA Grant NA46RG0472 to UC Sea Grant and the California State Resources Agency.) THE IMPORTANCE OF LIFE HISTORY AND POPULATION STRUCTURE TO THE DESIGN AND EVALUATION OF MARINE RESERVES Mark Carr and Pete Raimondi |
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