The effect of water flow rate on the regeneration rate of the temperate sponge Cliona celata was investigated at two sites experiencing fast and slight current flow respectively at Lough Hyne, Co. Cork, Ireland. Faster regeneration rates were found in sponges living in high current areas which may be due to an increased amount of potential food material per unit time and the possibility of entrained water flow.

A bass tagging project on the south coast of Anglesey, 1971–5, yielded 86 recoveries from 912 taggings. In addition to expected local movements a systematic pattern of seasonal migration was identified for adults. Fish present in summer moved to south Cornwall for the winter, returning in succeeding summers for spawning. Departure was normally before mid-October. Fish present after that had summered further north (reaching Furness in warm summers). These too moved south as winter advanced, though possibly not reaching Cornwall. A few solitary fish – unfit specimens or members of weak year-classes – appeared to remain through the winter. No evidence was found of movement to, or intermingling with stocks of, the Irish coast; nor, with one exception, the mainland coast of Europe. There was also no indication of movement eastward along the south coast: suggesting discrete populations there from those on the west coast.

Some aspects of the reproductive biology of the polychaete Gorgoniapolynoe caeciliae have been described for the first time. Gorgoniapolynoe caeciliae is a deep-sea commensal species associated with Candidella imbricata, an octocoral that populates the New England Seamount chain. Gorgoniapolynoe caeciliae is a dioecious species with an equal sex ratio and fertile segments throughout most of the adult body. The gonads of both sexes are associated with genital blood vessels emerging from the posterior surface of most intersegmental septa. In the female, oogenesis is intraovarian with oocytes being retained within the ovary until vitellogenesis is completed. The largest female examined contained over 3000 eggs with a maximum diameter of 80–90 μm. In the male, the testes are repeated in numerous segments and consist of small clusters of spermatogonia, spermatocytes, and early spermatids associated with the walls of the genital blood vessels. Early spermatids are shed into the coelom where they complete differentiation into mature ect-aquasperm with a spherical head (4 μm), a small cap-like acrosome, and a short mid-piece with four mitochondria. Indirect evidence suggests that this species is an annual breeder that releases its gametes into seawater and produces a planktotrophic larva following fertilization. The reproductive biology of G. caeciliae is consistent with that of most other polynoids including many shallow water species suggesting that phylogenetic history strongly shapes its biology.

A theoretical study of the behaviour of ferric phosphate in sea water has been made with existing data. The conditions least favourable for the continued existence of ferric phosphate should occur in the upper layers of the sea during active plant growth. The formation and stability of ferric phosphate is likely to be most favoured under the more acid conditions found in the gut of many animals. Ferric phosphate is likely to be introduced into sea water in animal faeces. Experimental confirmation of this deduction is essential.

In all experimental work involving ferric phosphate in sea water, the need is indicated for very accurate control of hydroxyl-ion activity and probably pressure, and for attention to the time factor and to the physical condition of the precipitated phase. The topic is of geochemical as well as of biological interest.

Dipyridyl is a reagent for ferrous iron. Reasons are set out why in sea and lake water at high dilutions it may also determine ferric iron without presence of an added reducing agent.

Evidence is presented that ferrifluoride plays no part in the iron cycle in he sea.

A portable light-trap was designed and constructed to assist in Museum taxonomic studies on Crustacea. The trap was constructed throughout of transparent Perspex. The light-source was a chemoluminescent ampoule marketed under the name Cyalume® Lightstick. The present trap offers several advantages. It is inexpensive to construct, sturdy, readily portable, easy to operate, and safe to use. Field trials in Lough Hyne (Ine), Co. Cork, south west Ireland, have proved the apparatus to be most successful in attracting a wide variety of crustaceans.

Recently, the rich coral communities of the so called roche du large biocoenose of the Gulf of St Eufemia (southern Tyrrhenian Sea) between 90 and 130 m deep, have been described thanks to remotely operated vehicle (ROV) imaging. This preliminary survey evidenced the massive presence of a well-diversified sponge community living among the coral colonies. This work aims at giving an ecological overview of some of the dominant species of this environment, together with a taxonomic part including the description of new species: Topsentia calabrisellae sp. nov. and Haliclona (Soestella) fimbriata sp. nov. The silted, rocky outcrops of the Gulf of St Eufemia facilitate the settling mainly of massive sponges with erect habit which may also avoid sedimentation by growing on the coral colonies. On the other hand, the site Capo Vaticano, located at the southern boundary of the gulf, characterized by rocky boulders exposed to strong currents and completely devoid of corals, is inhabited by a poor megabenthic community, dominated by patches of massive sponges, such as Topsentia vaceleti, a species of recent description whose aspect in the field was still unknown. In the entire investigated area 19 species have been photographed (often for the first time in vivo), collected and identified, but the real sponge diversity is certainly under-estimated due to the difficulty of collecting all the sighted specimens through the ROV grabber. Similarly to the coral component, sponges also respond to the same environmental constraints by growing in heterogeneous patches or by showing different morphologies mainly associated with current and sedimentation conditions.

The volumetric and qualitative analysis of the food of Gadus minutus has been discussed. The post-larvae feed entirely on copepods, mostly Pseudocalanus elongatus. The O-group feeds on copepods, small decapods, amphipods, polychaetes and isopods. The adolescent and adult groups feed on larger decapods like Processa canaliculata, Galathea spp. and Portunus spp., fish, polychaetes and amphipods.

The age and rate of growth of G. minutus have been computed from a study of the supra-occipital crest. These age determinations have been correlated with the age determined by scales, otoliths and size-analysis. Back-calculations have been made by graphical method and by using the Lea-Dahl formula. The differences between the back-calculated lengths and actual observed lengths are negligible.

Coney (Cephalopholis fulva) otoliths were collected from 1997 to 1999 off the central coast of Brazil. Analysis of the edges of otoliths sections suggests that one translucent and one opaque zone are formed once a year. Coney age and size-ranges were 2–25 years and 172–428 mm total length (TL) respectively. The von Bertalanffy growth equation was TLt=316(1−e−0.138(t+5.301)). The maximum age observed in this study is well above that previously reported for coney.

The number of eggs produced by the herrings of the East Anglian shoals increases with the length of the fish at a rate equal to the 3·465 power of the length, and with the age of the fish to the 0·66 power of the age. This fecundity is compared with that found in other races of herrings.

The number of eggs produced is closely correlated with the mean weight of the ovary, and it is found that the weight of the ovary increases with length at a rate equal to the fourth power of the length, and that a slightly higher rate applies to the testis.

The weight of the gutted fish, however, increases in relation to the length at a much slower rate, namely, as the 2·3 power of the length in the males, and the 1·5 power of the length in the females.

Adult Pseudocalanus elongatus have been kept in the laboratory, and fed with a variety of algal grazing media. The survival under conditions of starvation has also been determined, and in this respect, the overwintering generation has been found to differ from other generations.

Isochrysis galbana, Phaeodactylum tricornutum, Gymnodinium veneficum, G. vitiligo, Chlamydomonas sp. and C. coccoides have been found to be satisfactory foods for Pseudocalanus elongatus

Dicrateria inornata, Nitzschia gotlandica, Amphidinium sp., Chlorella stigmatophora and Dunaliella tertiolecta were found to be unsatisfactory foods for Pseudocalanus elongatus.

Traditionally, colonies of encrusting epiphytic bryozoans have been regarded as biotic factors reducing photosynthetic performance in benthic algae. In this study we determined under laboratory conditions the effects of Membranipora tuberculata on the photosynthetic efficiency of the rhodophyte Gelidium rex.

Encrusting bryozoans reduce to 44% the incident light reaching the algal thallus. However, concentrations of chlorophyll a and other accessory pigments are significantly higher in encrusted than in non-encrusted thalli. Consequently, photosynthetic efficiency is almost identical in both types of thalli. Although non-encrusted thalli showed a higher photosynthetic V due to higher levels of light reaching the algae, encrusted thalli exhibited a compensatory effect at low photon flux density and reached a similar P value. The detrimental effect of M. tuberculata on photosynthesis could be partially compensated by CO released from bryozoan cells, as G. rex preferred CO over HCO3 as a source of photosynthetic inorganic carbon. These results suggest that physiological interaction between bryozoans and algae, involving the interchange of metabolic substances, are likely to be important.

A massive die-off of benthic suspension feeders (BSF) covered by large amounts of sediments was observed along Prince Islands coasts (north-eastern Sea of Marmara) in August 2015. Alcyonarians, pennatulaceans, bivalves and sponges were severely affected. Many BSF probably died from burial and clogging of their feeding and respiratory apparatus. Of the gorgonian colonies, 66 ± 34% (mean ± SD) were dead, while 15 ± 16% (mean ± SD) displayed recent necrosis on the colony surface. In addition, histopathological and microbial examinations of the affected gorgonians and gold corals (Savalia savaglia) suggest that stress caused by sedimentation made them vulnerable to exploitation by consistently isolated opportunistic microorganisms. We isolated Vibrio splendidus and Vibrio neptunius from diseased gold coral colonies, but the bacterial isolates obtained from gorgonians could only be identified to genus Vibrio level. The presumably artificially introduced fungus Mucor circinelloides was common on both gold coral and gorgonians. This mould and opportunistic bacteria may have colonized BSF by taking advantage of low oxygen levels leading to impaired coral immune responses and thereby exacerbated the BSF mortality. Construction and landfill operations at Yassıada seem to be the greatest contributor to the observed sedimentation, as shown by silicate concentrations in nearby waters. These observations imply that preventive measures are necessary when construction operations take place in the vicinity of sensitive marine habitats.

Cephalothorax length and dry weight of copepodite stages and adults of the planktonic copepod Acartia clausi Giesbrecht in the Saronikos Gulf, Greece, were measured. Length-weight relationships and condition factor were also determined. The results were based on 17 zooplankton samples collected between November 1989 and June 1990, a period in which the abundance of A. clausi is significant. There was an inverse relationship between temperature and length, a pattern shown by many copepods. Temperature had the most significant effect on length, which was also affected by chlorophyll level. This strong temporal variation in length might possibly be considered as an adaptation of A. clausi to a continuously fluctuating environment. Length-weight regressions displayed high coefficients of determination (r2=0.98). Food, expressed as chlorophyll, affected the size and condition factor, and could act as a limiting factor on length and weight of A. clausi in the study area.

Eggs of the capelin, Mallotus villosus, are laid superficially on sandy beaches where they may be exposed to temperatures below –5 °C during tidal emersion. The eggs do not freeze until the temperature of their surroundings falls to a mean of –11.9 °C for eggs at the late blastula stage and –10.6 °C for eggs about to hatch, even though films of sea water covering the eggs are frozen. Newly hatched capelin larvae freeze at a mean temperature of –2.5 °C when the sea water surrounding them freezes, and are probably supercooled at temperatures below this before hatching. Evidence is presented which demonstrates that capelin eggs survive low temperatures by supercooling, and that they can do so in the presence of external ice crystals because the chorion prevents ice penetration and hence seeding of the eggs' internal fluids. The chorion of Mallows is shown to possess an extra secondary layer, like that of the related smelts. The primary function of this outer layer appears to be be concerned with adhesion to sand grains but it seems likely that it also prevents or delays ice penetration.

The horse-mussel Modiolus modiolus (L.) is a bivalve molluse inhabiting coastal marine environments down to about 200 m, where it may occur in very large communities (Wiborg, 1946; Tebble, 1966; Comely, 1978). It can also be found low in the intertidal zone where it lives in rock pools or in the hold-fasts of Laminaria (Wilson, 1977; Davenport & Kjørsvik, 1982). It is a boreal species. In the Atlantic it ranges from the White Sea to the Bay of Biscay, off Iceland, the Faroes and down the east coast of North America to North Carolina. In the Pacific it occurs from the Bering Sea to Japan and California (Wiborg, 1946). Comparatively little work has been done on Modiolus modiolus, probably because it is of little commercial importance and lives predominantly subtidally in relatively inaccessible environments.

Investigations on the digestive enzymes of polychaetes have, in most cases, been limited to the presence or absence of protein (gelatin) digesting and starch digesting enzymes. These enzymes have been shown to be present in all the polychaetes that have been studied (Mansour-Bek, 1954; Dales, 1955; Marsden, 1963). The results for the lugworm, Arenicola marina (L.) have been varied. Recent work has indicated the presence of enzymes capable of digesting starch and gelatin in the oesophagus, oesophageal pouches and the stomach of the lugworm (Kermack, 1955). However, Brasil (1903) found that no digestion took place when secreted fluids of the oesophageal pouches were incubated with starch, though fibrin was digested both by these fluids and a water extract of the ‘caeca’. Nicol (1930) records the work of Krukenberg, who found that proteolytic enzymes were present in the gut of A. marina. Kermack (1955) noted that the stomach was slightly acidic, though Nicol (1930) records the work of Wirèn, who found that the contents of the ‘intestine’ and the ‘intestinal caeca’ of A. marina were alkaline. As there have been no detailed analyses of the digestive enzymes of the lugworm, a survey of the distribution of carbohydrases, proteases and lipases in the gut of A. marina was carried out, and the optimal range of the carbohydrases investigated.

When examining the gills of a lobster for specimens of Nicothoe large numbers of copepods were found which, colourless and slender in form, had the sluggish and rather aimless movements which one would expect from a commensal removed from its natural habitat. It was somewhat of a surprise to find that they all belonged to a species already described —Tisbe elongata A. Scott. Scott obtained a few specimens from mud collected on mussel beds between Heysham and Morecambe. It appears, then, that we have here a species which is capable of free life, but its abundance, in all stages of growth, in the gill chamber of a lobster, proves that it is also to be considered a semi-parasite.

There are not sufficient data available to allow any general statements about the earlier stages of evolution of the autonomic nervous system and of its various transmitter mechanisms. In the previous paper (Young, 1980) it was shown that control of the stomach of elasmobranchs is largely by the inhibitory action of the sympathetic nerves, probably mediated by 5-HT. In teleostean fishes on the other hand control seems to be mainly by the cholinergic excitatory action of the vagus, especially in the more advanced (acanthopterygian) groups (Grove & Campbell, 1979a, b; Fänge & Grove, 1979).

Sea trials, using baited pots (inkwell and French barrel) and nets (tangle and gill), were conducted for the spider crab Maia squinado off the west coast of Ireland from November 1978 to July 1980. A series of laboratory pot trials using inkwell pots were performed. Diving observations were made on the fishing grounds.

Catch per unit effort rose to a summer peak and decreased in autumn. There was no difference in size composition or sex ratio of the catch between the pots and nets. Mature males predominated in the catch with the highest male:female (M:F) ratios recorded in summer. Immatures were virtually absent from the catch. Segregation on the basis of sex and maturity appears to occur in summer. Mature males were found at about 10 m, in sandy areas with rocky outcrops. Mature females occurred at about 5 m, on a sand and shell gravel bottom with rock and weed (notably Laminaria). Immatures were rare and occurred just below the intertidal. The M:F ratio was lowest during the periods of the onshore and offshore migrations. Berried females were recorded from March to September with one brood produced each year.

Laboratory pot trials showed increased aggression among spider crabs in the presence of baited pots. Males drove other males away from pots and divided their time between agonistic encounters and searching. Females were not driven away and did not engage in aggressive encounters. This behaviour, and the observation that large males could reach the bait through the pot bars, possibly explains the absence of larger and smaller males from the pots.