TABLE 2 



Components (counts expressed as individuals/m') of neuston 



biocoenoses in the basic water area types of the tropical 



Pacific. 



B, in 

 mg/m * 



Component 



Basic water area type 

 Caroline South Open waters 

 Atoll China of the 

 lagoon Sea Pacific 



* This category groups together mesozooplankton components 

 found in the surface layer, but distinct from the enumerated 

 categories of organisms in being more uniformly distributed 

 over the water column. 



TABLE 3 



Dominance of organisms in neustal expressed as a 

 percentage. 



Sea area 



', 



Caroline Atoll lagoon 

 South China Sea 

 Open ocean 

 Marianas sector 



1.3 ±0.1 

 2.5 ±0.6 

 1.5 ±0.3 

 0.9 ± 0.4 



A degree of symmetry of neuston distribution with respect 

 to the equator was noted (see Fig. 1 ). This was evidence of the 

 effect of the northern and southern tradewind currents and of 

 the anticyclonic current between them, 



The observed pattern of organism distribution agrees with 

 the data of Voronina ( 1964), who established that peak counts 

 of the most common pontellid Pontella tenuiremis occurred at 

 1°N and 1 C S. The meridional components of surface current 



Fig. 1 . 



Latitudinal distribution of neuston biomass (B) in the tropical waters 

 of the Pacific Ocean. 



point outwards from the equator, so that species that inhabit the 

 topmost water layer are constantly carried away from it. The 

 departing water is replaced by deeper-lying water free of 

 surface animals. The result is an acute trough in surface species 

 along the equator (Sverdrup et al., cited by Voronina, 1964). 



Constituting an agglomeration of hydrobionts. neuston 

 attracts both aquatic and aerial predators. We know, for 

 example, that decapod crustacean and pontellid larvae are part 

 of the diet of tunas, bonitos, and other epipelagic fishes ( Marchal. 

 1959). Porpita are consumed by marine turtles, while fish 

 larvae and fry are food for marine snakes (Zaitsev, 1971). 

 Neuston animals are an important part of the diet of seabirds. 

 Flying fish are caught on the fly by frigate birds (Fregatidae) 

 and terns (Laridae). Procellariiformes birds (Puffinus) have a 

 variety of ways of feeding on neuston; albatrosses ( Diomedea) 

 and fulmars (Fulmarus) snatch their prey from the surface, and 

 fork-tailed storm-petrels (Oceanodroma) do so while 

 performing a "mincing walk" on water (Boaden& Seed, 1985). 

 In waters close to shore, neuston is eaten by skimmers 

 (Rhynchopidae) with their long cultiform gonys (Zaitsev, 

 1971 ). According to the latest count (Day et al., 1984). there 

 are at least 50 species of birds that feed on neuston. 



In conformity with what is usually the case with distribution 

 in the ocean, neuston is most profuse in areas where currents 

 converge. However, recent decades have seen a proliferation 

 in the same areas of various kinds of plastic debris ( Day et al. , 

 1984). Looking for neuston, marine birds often swallow these 

 foreign objects, whose effect is invariably harmful and often 

 fatal. With their high adsorption coefficients, oil lumps and 

 plastic objects tend to have a buildup of toxic substances on 

 their surface (Osipov & Charykov, 1987), thus inhibiting the 

 development of invertebrates and fishes in the neustal. This, in 

 turn, can only have a negative impact on the bioproductivity of 

 the entire ocean. 



224 



