Rafting of marine and terrestrial organisms has been reported from a variety of substrata and from all major oceans of the world. Herein we present information on common rafting organisms and on ecological interactions during rafting voyages. An extensive literature review revealed a total of 1206 organisms, for which rafting was confirmed or inferred based on distributional or genetic evidence. Rafting organisms comprised cyanobacteria, algae, protists, invertebrates from most marine but also terrestrial phyla, and even a few terrestrial vertebrates. Marine hydrozoans, bryozoans, crustaceans and gastropods were the most common taxa that had been observed rafting. All major feeding types were represented among rafters, being dominated by grazing/boring and suspension-feeding organisms, which occurred on all floating substrata. Besides these principal trophic groups, predators/scavengers and detritus-feeders were also reported. Motility of rafting organisms was highest on macroalgae and lowest on abiotic substrata such as plastics and volcanic pumice. Important trends were revealed for the reproductive biology of rafting organisms. A high proportion of clonal organisms (Cnidaria and Bryozoa) featured asexual reproduction, often in combination with sexual reproduction. Almost all rafting organisms have internal fertilisation, which may be due to the fact that gamete concentrations in the rafting environment are too low for successful fertilisation of external fertilisers. Following fertilisation, many rafting organisms incubate their offspring in/on their body or deposit embryos in egg masses on rafts. Local recruitment, where offspring settle in the immediate vicinity of parents, is considered an important advantage for establishing persistent local populations on a raft, or in new habitats. Some organisms are obligate rafters, spending their entire life cycle on a raft, but the large majority of reported rafters are considered facultative rafters. These organisms typically live in benthic (or terrestrial) habitats, but may become dispersed while being confined to a floating item. Substratum characteristics (complexity, surface, size) have important effects on the composition of the rafting community. While at sea, ecological interactions (facilitation, competition, predation) contribute to the community succession on rafts. Organisms capable to compete for and exploit resources on a raft (space and food) will be able to persist throughout community succession. The duration of rafting voyages is closely related to rafting distances, which may cover various geographical scales. In chronological order, three features of an organism gain in importance during rafting, these being ability to (1) hold onto floating items, (2) establish and compete successfully, and (3) develop persistent local populations during a long voyage. Small organisms that do not feed on their floating substratum and with asexual reproduction or direct development combine all these features, and appear to be most suited for long-distance dispersal on rafts and successful colonisation after reaching new habitats. All available evidence suggests that rafting is an important process for the population dynamics of many organisms and that it also has had and continues to have a strong influence on coastal biodiversity.

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The Ecology of Rafting in the Marine Environment. II. The Rafting Organisms and Community

FAS 5407 Biology of Fishery and Aquaculture Invertebrates 3 Credits Grading Scheme: Letter Grade Examines the biology of marine and freshwater invertebrates that are important as fisheries or in aquaculture. Topics will include taxonomy, morphology, distribution, habitat requirements, nutrition, major predators and parasites, significant ecological interactions, and life cycles. Nonfood fisheries, such as commercial sponges and pearl oysters, will be included.

Fisheries and aquatic sciences

Pelagic fisheries Habitat selection and migration Schooling behaviour Avoidance Attraction and association Learning Effects of behaviour on fisheries and stock assessment by population dynamic models Effects of behaviour on stock assessment by acoustic surveys Other methods of stock assessment and fish behaviour.

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Dynamics of pelagic fish distribution and behaviour : effects on fisheries and stock assessment

https://www.mbara.org/pdf/PickeringWhitmarsh_97_avp.pdf

Artificial reefs and fisheries exploitation: a review of the ‘attraction versus production’ debate, the influence of design and its significance for policy

An immense variety of fish may, on occasions, aggregate around or beassociated with floating structures such as drifting algae, jelliedzooplankton, whales, floats or anchored fish aggregating devices (ineffect, there are over 333 fish species belonging to 96 familiesrecorded in the literature).

A general theory on fish aggregation to floating objects: An alternative to the meeting point hypothesis

Artificial structures positioned off Panama City, Florida, during July 1969 proved effective in attracting commercial quantities of round scad, Spanish sardines, and scaled sardines. The structures' position in the water column and their design were important in attracting fish. Midwater structures which resembled a small pup tent were effective in attracting up to 25 metric tons of fish and consistently attracted frown 1/2 to 5 metric tons daily. SCUBA divers made visual estimates of the number of each species present at the structures. We discuss the behavior of the fish and present a possible explanation of why fish are associated with submerged structures.

Attraction of Coastal Pelagic Fishes with Artificial Structures

Field experiments were conducted in the northeastern Gulf of Mexico off Panama City, Florida to evaluate the feasibility of using man-made midwater structures for attracting pelagic game fish to improve sportfishing catch rates. Significantly greater catches of little tunny (Euthynnus alletteratus), king mackerel (Scomberomorus cavalla), and dolphin (Coryphaena hippurus) were made around experimental structure sites than in adjacent control areas when equal experimental fishing effort was used. Multiple structures attracted larger numbers of coastal pelagic bait fish and produced larger catches of pelagic game fish than single-structure units. The distance offshore or water depth of structure locations affected both the species of fish attracted and the number of fish caught. Charter fleet vessels fished around one of the experimental structures for several hours and reported total numbers of pelagic game fish caught and catch rates at least double those in “other areas” for that day.

The Efficacy of Midwater Artificial Structures for Attracting Pelagic Sport Fish

Field experiments were conducted in the northeastern Gulf of Mexico to evaluate techniques for using sequentially-operated lamp strings and moving lamps to lead and concentrate light-attracted coastal pelagic fishes. Fish were successfully led between sequentially-operated under-water lamps separated by distances up to 20 meters. Mobile lamps were used to lead fish distances up to approximately 1 kilometer. Fish aggregations which form daily around man-made structures were held after dark and led clear with moving lamps for capture by purse seine. A combination of nightlighting and man-made structure fish attraction techniques are proposed for harvesting coastal pelagic fish aggregations which occur around existing petroleton drilling platforms, well heads, and other areas presently inaccessible to conventional fishing gear.

Donald A. Wickham

Papers

Attraction of Coastal Pelagic Fishes with Artificial Structures

The Efficacy of Midwater Artificial Structures for Attracting Pelagic Sport Fish

Attracting and Controlling Coastal Pelagic Fish with Nightlights

Apparatus for Controlling Ambient Light Cycles in Experimental Environments