WORKSHOP SYNOPSIS Censusing Non-Fish Nekton Carohln Levi, Gregory Stone and Jerry R. Schubel New England Aquarium ° Boston, Massachusetts USA his is a brief summary of a "Non-Fish SUMMARIES OF WORKING GROUPS Nekton" workshop held on 10-11 December 1997 at the New England Aquarium. The overall goals Cephalopods were: (1) to assess the feasibility of conducting a census New higher-level taxa are yet to be discovered, of life in the sea, (2) to identify the strategies and especially among coleoid cephalopods, which are components of such a census, (3) to assess whether a undergoing rapid evolutionary radiation. There are periodic census would generate scientifically worth- great gaps in natural history and ecosystem function- while results, and (4) to determine the level of interest ing, with even major commercial species largely of the scientific community in participating in the unknown. This is particularly, complex, since these design and conduct of a census of life in the sea. short-lived, rapidly growing animals move up through This workshop focused on "non-fish nekton," which trophic levels in a single season. were defined to include: marine mammals, marine reptiles, cephalopods and "other invertebrates." During . Early consolidation of existing cephalopod data is the course of the workshop, it was suggested that a needed, including the vast literatures in Japanese more appropriate phase for "other invertebrates" is and Russian. Access to and evaluation of historical invertebrate micronekton. Throughout the report we survey, catch, biological and video image data sets have used the latter terminology. and collections is needed. An Internet-based reposi- Birds were omitted only because of lack of time. tory, e.g. "Cephalopod Base," similar to "Fish Base," Within the reptile group, snakes and crocodiles were would help in consolidation and access and help get underrepresented; in the marine mammal group, pin- people up to speed for new projects. Support for nipeds were underrepresented. However, for the Russian scientists and recent Ph.D.s could help solve purposes of the workshop these deficiencies are not fatal. the lack of human resources. Four white papers were commissioned to provide a point of departure for discussion at the workshop. The mesopelagic region has the greatest potential to The four papers deal with (1) marine mammals, yield most new insights. It has the largest biomass (2) cephalopods, (3) invertebrate micronekton and and greatest diversity, including the enormous (4) marine reptiles. biomass in the deep scattering layer, and it is doable The participants ranked the categories of animals in with technology we already have or could develop terms of estimated biomass (Table 1) and knowledge in a couple of years. Sampling techniques need to be relative to what remains to be learned (Table 2.) cross correlated and improved. We suggest a multi- ple gear approach, combining manned submersible and ROV images, optical scanning technologies, net TABLE I TABLE 2 sampling, and multiple acoustic technologies. Non-Fish Nekton Ranked in Non-Fish Nekton Ranked in Include marine mammal tagging and tracking and Decreasing Order by Biomass* Decreasing Order of State of Knowledge Relative to What intense sampling in areas where whale studies are Invertebrate Micronekton Remains to Be Learned ongoing or possible. Cephalopods Marine Mammals 3. The paralarvae of mesopelagics are currently uniden- Marine Mammals Marine Reptiles tifiable. DNA techniques could link life history stages and lay groundwork for studies of cryptic speciation. Marine Reptiles Cephalopods 4. Archival radio pop up tags could work for learning *Biomass of invertebrate micronektonprobably Invertebrate Micronekton exceeds the biomass of the other three about larger species of ammoniacal squids - categorm combined. Histioteuthis and Molvteuthis - in the mesopelagic region. Oceanography • VoL 12 • No. 3/1999 15 5. Participate in four location intensive and four tran- Bag 2. Worldwide inventories sect mesopelagic censuses with the Invertebrate 1. Space imagery Micronekton group. With the Invertebrate (a) aggressively pursue this option to test its limits Micronekton group, we identified the location- and applicability. intensive sites as: (b) turtle beach assessments, pinniped haulouts, (a) The canyons of the south side of Georges Bank polynyas, breeding lagoons, and the feasibility and the "Gully," off Sable Island, Nova Scotia of counting some whale species (belugas, grays, (the Gully is rich in Histioteuthis and sperm rights). whales). (c) investigate high resolution infrared for night (b) Bahamas/Caribbean time and Arctic assessments. (c) Monterey Bay (d) Sagami Bay, Japan . Surveys of regions These surveys would also benefit a census of (a) integrate survey planning with other ongoing micronektonic fishes. Include collaboration with data collection and archival organizations. "cetacean samples" and a day/night regime. (b) aerial (standard transect methods). (c) shipboard (transects, plus oceanography, Marine Mammals molecular biology, and acoustics). A review of marine mammal distribution and (d) quadrant sampling (predetermined stations, abundance led us to conclude the largest gaps in our with observing and sampling of oceanography, knowledge centered around interactions and functions biology at all trophic levels, acoustics, benthic within habitats. In many cases, we don't know where ecology, and molecular biology). appropriate surveys should begin and end (i.e. the (e) nuclear submarines as research platforms. ranges and seasonal movements of animals are poorly (f) acoustic tomography assessment of biomass. defined or unknown). Greatest value will come from (g) needs are in developing countries, feasibility counting populations that are rapidly increasing or studies may be more cost effective in areas decreasing or that are moving around over a lot of where more baseline information is available. ocean. To make a quantum leap forward in understand- (h) base surveys on earlier telemetry work. ing the worldwide distribution, behavior, abundance, (i) include and assess human activities within diversity, and ecological roles of marine mammals, we every survey protocol. outlined the following prioritized strategy, which is dependent upon three or four large Bag 3. Modeling bags of money. Greatest value will come 1. Use the data collected from the first from counting populations two bags to develop system models Bag 1. New Devices (e.g. satellite that are rapidly increasing or that will provide predictive power for telemetry, miniaturized sensors, bells trends in distribution and abundance and whistles; 50,000 tags are needed, a decreasing or that are moving vs. changes in habitat, global climate, 1000-fold increase in tagging) around over a lot of ocean. human activities, and the price of 1. What can we measure or obtain: pork bellies. (a) light, color, temperature, salinity, orientation, position, sound, chemical and olfactory cues, biolu- Bag 4. Repeat in x years, where x is something less than minescence, visual imagery, physiology. 100. Additionally, we predict that new species will come . What will it teach us? primarily from "splitting" rather than new discoveries. (a) oceanographic and sea-truth sampling stations. (b) the definition of home ranges, seasonal move- Invertebrate Micronekton ments, and habitat use patterns, which will help define subsequent survey requirements. We want to assess the diversity and abundance of (c) G (0) corrections - dive time data to allow cor- mesopelagic animals. This is the largest habitat on earth rections to survey data on the amount of time an and it contains the least known major faunal groups. animal is present at the surface. 1. The recommended approach is ecological and func- (d) information about physiology, prey, feeding tional rather than strictly taxonomic: Identifying behavior, habitat use and oceanography correlated animals in the context of their ecological roles or in 3D, with emphasis on the scattering layer. niches, and using this framework as a means of 16 Oceanography • VoL 12 • No. 3/1999 categorizing and organizing the data on their diver- 2. Apply sampling techniques on a worldwide basis sity and abundance. to ascertain global status of seven species. 2. This approach would be best initiated by working . To develop and fully utilize remote sensing-derived first in an area or areas where a basic data set exists information to provide or improve precision of cen- (coastal), using this information to create the eco- sus information for nesting females, pelagic, and logical framework, then expanding the scale of benthic life history stages. operations to include boundary current and central gyral regions. 4. To develop and deploy a permanent tag that will 3. The recommended technological and methodologi- provide information on migratory routes, age, mor- cal approach involves both remotely operated tality, and other information, and to build and vehicles and manned submersibles to conduct in maintain an accessible database. situ surveys and sampling in the upper 1000m of the water column. To develop and utilize remote sensing technologies to map habitat types, and together with satellite . These platform technologies would be supplement- tags (of some type), to determine migratory routes ed by acoustic and optical instrumentation which and pelagic habitat preferences. themselves would be integrated to maximize their survey effectiveness. Predicting where turtles are, based on habitat pref-