Behavior ecology of the Humboldt squid, Dosidicus gigas: insights from an animal-borne video and data logging system

Dosidicus gigas is a large pelagic cephalopod of the eastern Pacific that has recently undergone an unexpected, significant range expansion up the coast of North America. The impact that such a range expansion is expected to have on local fisheries and marine ecosystems has motivated a thorough study of this top predator, a squid whose lifestyle has been quite mysterious until recently. Unfortunately, Dosidicus spends daylight hours at depths prohibitive to making observations without significant artificial interference. Observations of this squid‟s natural behaviors have thus far been considerably limited by the bright illumination and loud noises of remotely-operated-vehicles, or else the presence of humans from boats or with SCUBA. However, recent technological innovations have allowed for observations to take place in the absence of humans, or significant human intrusion, through the use of animal-borne devices such as National Geographic‟s CRITTERCAM. Utilizing the advanced video recording and data logging technology of this device, this study seeks to characterize unknown components of Dosidicus gigas behavior at depth. Data from two successful CRITTERCAM deployments reveal an assortment of new observations concerning Dosidicus lifestyle. Tri-axial accelerometers enable a confident description of Dosidicus orientation during ascents, descents, and depth maintenance behavior - previously not possible with simple depth tags. Video documentation of intraspecific interactions between Dosidicus permits the identification of ten chromatic components, a previously undescribed basal chromatic behavior, and multiple distinct body postures. And finally, based on visualizations of spermatophore release by D. gigas and repetitive behavior patterns between squid pairs, this thesis proposes the existence of a new mating behavior in Dosidicus. This study intends to provide the first glimpse into the natural behavior of Dosidicus, establishing the groundwork for a comprehensive ethogram to be supported with data from future CRITTERCAM deployments. Cataloguing these behaviors will be useful in accounting for Dosidicus‟ current range expansion in the northeast Pacific, as well as to inform public interest in the impacts this expansion will have on local fisheries and marine ecosystems.

Assessment of institutional contexts for collective action, and stakeholder receptiveness to integrated research-extension approaches on Lac Ntomba, Lac Maï-Ndombe and the Maringa-Lopori-Wamba watersheds

The WorldFish Center has been collaborating with its partners (AWF and WWF) in the Maringa-Lopori-Wamba (MLW) and the Lac Tele-Lac Ntomba (LTL) Landscapes to develop participatory monitoring systems for aquatic ecosystems. This requires rigorous data collection regarding fishing effort and catch, and the establishment of community partnerships; enabling WorldFish Center researchers to understand and counteract the institutional legacies of previous NGO interventions. In the MLW, fisherfolk livelihoods are severely limited due to their extreme isolation from markets and government services. However, fisherfolk have some experience dealing with natural resource conservation or extraction entities as well as humanitarian agencies. Their history has left them slightly skeptical but reasonably willing to collaborate with incoming NGOs. Around Lac Ntomba, fisherfolk have had more extensive interactions with conservation and humanitarian NGOs, but despite their proximity to the Congo River, they appear to have very limited access to distant markets. As past benefits from NGO activities have been captured by local village elites many fishers are highly skeptical and even antagonistic toward NGOs in general, and see little benefits from collaborating with each other or NGOs. Similarly to the MLW and Lac Ntomba, Lac Maï-Ndombe fisherfolk were disillusioned by past NGO activities. However, in this area levels of fish catch are greater than in the other watersheds, and many fishers make regular trips to major markets in Kinshasa, Kikwit and Tchikapa. Consequently, while there are significant divisions to be addressed in Lac Maï-Ndombe, fisherfolk in general are more interested in exploring options for improving livelihoods. In order to overcome these hurdles, the WorldFish Center has introduced an integrated research-extension approach in its interactions with these communities. The teams conducted demonstrations of technological innovations that could significantly improve on present post-harvest fish processing practices, in particular: a solar fish drying tent and a fish smoking barrel.

Technological aspects of processing of edible mussels, clams and crabs. Pt. 1. Spoilage during ice storage

Rate and pattern of spoilage of some of the economically important edible species of shell fishes Mytilus edulis (Mussel), Villorita cornucopia (Clam), Neptunus pelagicus (Crab) and Scylla serrata (Crab) have been discussed in this communication. Chemical indices used for objective evaluation of quality were water extractable nitrogen (WEN), non-protein nitrogen (NPN), free α-amino nitrogen (α - NH2 -N), glycogen, lactic acid and inorganic phosphorus in addition to the subjective tests. No significant difference in the spoilage pattern of the species during ice storage was observed and these species could be preserved in ice in organoleptic acceptable condition up to 8 days, 9 days, 8 days and 11 days respectively.

Technological aspects of preservation and processing of edible shell fish 2. Influence of season on the chemical composition of crab (Scylla serrata)

The purpose of this communication is to bring out the influence of season on the chemical composition of crab, covering a period of 2 years. Changes in moisture, protein, water extractable nitrogen, non-protein nitrogen, glycogen, lactic acid, fat and free amino acid composition of crab meat have been reported on a monthly basis.