Southern California Bight 2003 Regional Monitoring Program: IV. Demersal Fishes and Megabenthic Invertebrates
Species Richness (Number of Species) per Haul
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Species Richness (Number of Species) per HaulA total of 308 species of invertebrates were collected during the survey (Table V-5). The number of species per haul ranged from 0 to 37. No invertebrates were caught in at least one station in the north and south mainland regions, in bays, and on the mainland outer shelf. The single highest number of species (37) was caught in the northwest island region on the middle shelf. The median for the Bight as a whole was 12 species per haul, with subpopulation medians ranging from 4 (inner shelf, small POTWs ) to 16 (Islands region and northwest and southeast islands subpopulations). The number of invertebrate species was higher (more area above the Bight median) on the islands than the mainland regions. All island subpopulations had median numbers of species above the Bight median (Table V-5), and varied little amongst themselves. Mainland region medians were similar, although the central region median was about 30% higher (13 species/haul). By depth, the middle and outer shelf zones had the same medians, with the upper slope slightly lower (Table V-5). Bays (7 species) and the inner shelf (5 species) had considerably lower medians. Within the outer shelf zone, the median number of species was highest at the islands, followed by the mainland non-POTW subpopulation, with the single large POTW site on the outer shelf being lower than the latter median (Table V-5). Within the middle shelf, islands had the highest median, followed by the large POTWs and mainland non-POTW areas, with small POTWs having the lowest median. Overall, the inner shelf had low species richness medians, and the islands had the highest. Comparing regions within shelf zones, the highest medians in the middle and outer shelf zones were at the northwest islands (Table V-6). Overall, 20 stations had more than 19 species, with 7 of these occurring around islands (Figure V-3). The remaining high richness sites were nearly evenly distributed between the northern, central and southern mainland regions. Most (86) stations had 4 to 11 species, with 46% of the sites having 12 or more invertebrate species. Two sites, one in southern San Diego Bay and one off Ventura, had no invertebrates in the haul. Table V-4. Megabenthic invertebrate biomass by region within shelf zone subpopulations at depths of 2-476 m on the southern California shelf and upper slope, July-October, 2003. 
Table V-5. Megabenthic invertebrate species by subpopulation at depths of 2-476 m on the southern California shelf and upper slope, July-October 2003. 
Table V-6. Megabenthic invertebrate species by region within shelf zone subpopulations at depths of 2-476 m on the southern California shelf and upper slope, July-October, 2003. 
Figure V-2. Distribution of megabenthic invertebrate biomass per haul at depths of 2-476 m on the southern California shelf and upper slope, July-October 2003. 
Figure V-3. Distribution of megabenthic invertebrate species per haul at depths of 2-476 m on the southern California shelf and upper slope, July-October 2003. Diversity per HaulInvertebrate diversity ranged from 0.0 to 2.77 bits/individual/haul (Table V-7). Values of zero occurred at all three mainland regions, and in inner and outer shelf zones. The highest diversity occurred in the northwest island middle shelf. The median for the Bight as a whole was 1.10 bit/individual/haul, with subpopulation medians ranging from 0.10 (outer shelf, large POTW) to 2.35 (island upper slope). Invertebrate diversity was higher (more area above the Bight median) at the islands than at the mainland: medians were 1.71 and 0.96, respectively (Table V-7). Among the islands, the cool northwest islands had a greater median diversity (2.15) than the warm southeast islands (1.22). Along the mainland, the southern region had a higher median diversity (1.20) than the Bight and northern (0.95) and central mainland regions (0.90). Among depth zones the middle shelf had the highest diversity, followed by the outer shelf, bays, upper slope, and inner shelf; medians were 1.17, 1.15, 1.10. 0.96. and 0.90, respectively. On the outer shelf, islands had a higher median diversity than mainland areas. On the middle shelf, only mainland non-POTW sites did not exceed the Bight median (Table V-7). Comparing regions within the shelf zones, the highest diversity medians occurred at northwest islands in the middle shelf, outer shelf, and upper slope zones; in the northern region, the highest median was in bays (Table V-8). Invertebrate diversities exceeding 2.05 occurred at 21 stations distributed throughout the SCB. One- third of these occurred at the islands, and one in San Diego Bay (Figure V-4). The remainder were located on the mainland shelf in the central (4) and southern (6) regions. Most (85) stations had diversity values ranging from 1.14 to 2.05. Directory: pub -> download pub -> Acm word Template for sig site pub -> The german unification, 1815-1870 pub -> Baltic Olympiads in Informatics: Challenges for Training Together pub -> Preparation of Papers for ieee transactions on medical imaging pub -> Forthcoming meetings and conferences pub -> Asilomar Conference on Circuits, Systems & Computers, Pacific Grove, ca, November 1978, pp. 55 58 pub -> Forthcoming meetings and conferences pub -> Harmonised compatibility and sharing conditions for video pmse in the 7 9 ghz frequency band, taking into account radar use Download 11.21 Mb. Share with your friends:
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