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- erences will allow census sampling to be more effi- . Traditional acoustic and trawl sampling would also cient and more meaningful. be integrated into the program. . For some life history stages, catch per unit effort . This effort would include cephalopods and midwa- may be estimated rather than absolute abundance; ter fishes as well as the invertebrate micronekton. however, sampling must be conducted globally. Additional added value would accrue from integra- tion with surveys of other nekton (e.g. fishes, . Aerial or remote survey techniques will be devel- whales, turtles). oped that will allow census for all species in all areas of the globe, particularly those that currently . The effort is based on existing technologies, albeit lack coverage. with some in novel applications and combinations. . For long-lived species (sea turtles and the like) . We believe that this approach is feasible and would research commitments must be long-term in order be cost-effective for closing the largest gaps in our to develop meaningful time series. understanding of marine biodiversity. 10. This information, once gathered, can be utilized to develop predictive population models to Marine Reptiles (Sea Turtles) track/evaluate recovery of depleted populations worldwide. While sea turtle ranges have been delimited to some extent - through data collected in targeted fisheries, 11. On priority basis, we need to target world oceans incidental takes and strandings - most studies are con- where we have the least information on sea turtle centrated on nesting beaches. These include the more populations. accessible, identifiable beaches and leave all but nesting females and hatchlings largely unaccounted for. Gaps Do we need a census? Yes. Are we interested in par- in assessment, understanding turtle functions within ticipating? Yes. Do we want collaborators? Yes, espe- their habitats, and understanding life history include cially from the marine mammal group, with which we not knowing where pelagic juveniles go after reaching a share tagging technology needs. certain size; how many turtles are nesting on a world- wide basis; and many reproductive parameters, includ- ing the size of reproductive units and whether or not CONCLUSIONS AND RECOMMEN- nesting populations are unique stocks. DATIONS FOR WHICH THERE WAS We have identified the following major UNANIMITY OR NEAR UNANIMITY gaps/research needs (with the caveat that our "group" consisted of two persons): . There was unanimity that "it" is worthwhile, that the group wants "it" They want "it" as soon as they 1. Study nesting assemblages as population/repro- can get "it," as much of "it" as they can get, and for ductive units. as long as they can get "it."

Oceanography • VoL 12 • No. 3/1999 17 . We seek a fundamental understanding of the way . Animals have great underutilized potential as things live and die in the sea. "platforms" for research. The application need not be restricted to large mammals and reptiles. . There is more than one metric of abundance; in Animals equipped with sensors could provide some cases biomass (e.g. cephalopods) may have invaluable information about diversity, abundance, more meaning than numbers of individuals. We distribution, behaviors, and oceanographic para- would like to quantify biomass at least in the top meters. Breakthroughs will depend upon advances trophic levels, and across the age spectrum of in the tag industry. These advances must include species. We may be able to predict productivity not only making tags smaller and of lower power from biomass and energetics. requirements and longer battery life, but also a mat- uration of the tag manufacturing industry to meet . Collaborations will add value to any efforts to take the anticipated demands for far greater numbers of a census of life in the sea: collaborations between tags. At present, tags are manufactured one at a technologists and marine biologists; collaborations time by several small firms in a very small cottage between physical oceanographers and biological industry. oceanographers; and collaborations among scien- tists interested in different animal groups. . The value of simply having more ship and sub- mersible time should not be underestimated. Every . Technology was a recurrent theme throughout the new expedition leads to greater understanding, and discussions. There was a strong consensus that often to entirely new discoveries, particularly when existing technologies had not been fully exploited, there are trained observers on board. We have not particularly the opportunities for marrying differ- fully utilized the technologies we already have. ent kinds of technologies such as acoustic and optical sensors, and for exploiting advances in com- . Of looming concern, especially in the cephalopod puter technology, sensors, and submersibles. Other and micronekton groups, is that a census will be technologies that offer particular promise are "crit- constrained by the small population size and poor ter cams" and tags. By ground-truthing remote funding of systematists. There are few people qual- technologies against sampling, we would like to ified to identify the animals we want to census, and remotely identify taxa, to the species level, where career paths for new systematists are limited. possible.

Credit: NOAA

18 Oceanography • Vol. 12 • No. 3/1999