Age,growth and mortality of scaldfish (Arnoglossus laterna Walbaum, 1792) from the Adriatic Sea

The population dynamics parameters of scaldfish, Arnoglossus laterna, from the Adriatic Sea were studied. Specimens ranging from 4.5 to 17.1 cm in total length were collected from commercial bottom‐trawl catches (2000–2006). Spawning from April through the end of August with a peak in May, A. laterna is one of the non‐target species usually present in mixed bottom trawl catches. The overall male to female ratio was 1.00 : 0.61. The oldest individual was 6 years of age. Length–weight relationships showed positive allometric growth (b = 3.36 for males and b = 3.39 for females). Parameters of the von Bertalanffy growth equation were: L_∞ = 17.3 cm; K = 0.258 per year; t₀ = ?1.0026 year; R² = 0.925. The relatively low value of total mortality (Z = 0.90) and relatively high value of constant rate of natural mortality (M = 0.64) was estimated. Presumed calculated fishing mortality (F = 0.26) and the consequently estimated exploitation ratio (E = 0.29) indicated no danger of an over‐exploitation of this species in the study area at the current level of fishing pressure. The low T max and correspondingly high M suggest that this small benthic predator plays an important role in the Adriatic ecosystem as a prey species for large benthic predators. However, the estimates include uncertainties and require further confirmation, especially with regard to natural mortality.     

The occurrence of young scaldfish Arnoglossus latevna (Walbaum, 1792) in the eastern Irish Sea

Unusually high numbers of scaldfish have been found in the eastern Irish Sea during 1990. Advantageous climatic conditions may be responsible. The impact of this predator on inshore flatfish nursery populations may be important.     

The biology of the Norway goby, Pomatoschistus norvegicus (Collett), on the west coast of Scotland

The biology of the small offshore goby, Pomatoschistus norvegicus (Collett), was studied on the west coast of Scotland over a period of 19 months. Catches were highest in April-June and lowest in August-September. Virtually all growth takes place in the first two summers, very little in those fish surviving to a third summer. The fish mature after their first winter and the breeding season lasts from March-July. Fecundity is linearly related to standard length and varies from approximately 1000–4000 eggs. Approximately 75% of fish survive their first breeding season but all die after their second. Males live slightly longer than females. The diet consists mainly of amphipods and small caridean decapods. The life history ofthe species is compared with other members ofthe genus.     

The fish populations of inshore waters of the west coast of Scotland. The unusual occurrence of the blue whiting (Micromesistius poutassou) and some notes on its biology

This paper records the unusual occurrence of the blue whiting ( Micromesistius poutassou ) from inshore waters of the west coast of Scotland from 1971 to 1974. The fish were O and I-group and appeared to migrate into the area during the autumn and winter months. Data on growth, length for weight relationships and feeding are described.     

Aspects of the biology of the spotted dragonet Callionymus maculatus Rafmesque-Schmaltz from the west coast of Scotland

The biology of a Scottish population of the spotted dragonet Callionymus maculatus was studied from February 1975 to September 1976. The data were taken from monthly samples totalling over 700 fish trawled in 18–36 m on a soft mud bottom. Neither otoliths nor radial bones were found to be suitable for age determination, but evidence from other sources suggested that most growth takes place in the first two years of life and that males grow faster, but do not live as long (at least 3 years) as females (at least 5 years). Examination of the gonads showed that the spawning season probably lasts from April to September, that females mature earlier in life than males and are serial spawners. The males may reach first maturity at different ages. The sexes are markedly dimorphic. The rays of the dorsal, anal and caudal fins grow isometrically in females but growth of these organs in males is allo-metric after maturity has been achieved. The fish feeds predominantly on polychaetes and amphipods, although bivalve molluscs, macruran decapods and ophiuroids also occur frequently in its diet. There is some difference in the diet between length classes, smaller fish taking fewer polychaetes and more amphipods than the larger individuals. The species is finally compared with other dragonets whose biology is known.     

Growth, diet and condition of goldsinny on the west coast of Scotland

A study of seasonal, locational and sexual variations of growth, diet, somatic condition ( K _s), gonadosomatic condition (GSI) and hepatosomatic condition (HSI), of the goldsinny wrasse, Ctenolabrus rupestris , was made on specimens taken from three areas (Millport, Oban and Luing) of the west coast of Scotland from May 1992 to June 1993. Capture throughout the year was by either baited creel or by anaesthetics applied underwater. Male goldsinny of age 1 year and older ranged in total length from 67-155 mm, total weight 3.8-58.8 g, and had a maximum age of 14+ years. Females of 1 year and older ranged in total length from 59-159 mm, total weight 2.4-65.4 g and had a maximum age of 20+ years. Juvenile (0 +) goldsinny were mostly of indeterminate sex, ranged in total length from 16-57 mm, and total weight 0.08-1.97 g. Female growth was slower than that of males for all three locations; growth of male and female goldsinny from Millport was slower than the respective sexes at the other two locations. Length-weight relationships varied with age and location. There were differences in K _s, GSI, HSI and dietary trends associated with variation in season, sex and location. The implications of this variation are discussed in relation to the management of a sustainable goldsinny fishery.     

Distribution and density of populations of goldsinny wrasse (Ctenolabrus rupestris) on the west coast of Scotland

A field survey of populations of goldsinny wrasse ( Ctenolabms rupestris ) was undertaken on selected areas of rocky coast of west Scotland. Observations by sub-aqua diving were used to determine distribution, habitat preference, and population density, and their seasonal variations. Availability of the preferred refuge type (crevices on rock faces, or between boulders, where two or more entrances exist) was essential in determining goldsinny presence. Goldsinny were not always present in areas or at depths where the influences of freshwater runoff (low temperatures and salinities) were likely, even if the preferred habitat type was available. In areas remote from these influences, and where there were suitable refuges, depth of water (0–44 m), macroalgal cover and high current speeds (2.1–3.6 ms⁻¹) did not affect goldsinny distribution. Observed densities of goldsinny reached a peak in summer months with a maximum of 4.0 m⁻² in areas of shallow boulder scree, but only 1.0 m⁻² in shallow areas with little scree, or at deeper study sites. Numbers of goldsinny observed actively swimming decreased after October, with a rapid disappearance in November. A gradual reappearance was recorded in late April, and early May. Changes in activity may be influenced by both water temperature and photoperiod. Young-of-the-year goldsinny were first observed in August in shallow water (0–8 m) areas typified by rock/boulder scree and/or high macroalgal cover. Where adults also inhabited these nursery areas, 0+ fish could make up over 50% of the total population. After their first winter, juvenile goldsinny may migrate away from inshore sites.     

Annual compositional variation in wild Osmundea pinnatifida (Hudson) Stackhouse from the west coast of Scotland

Journal of Applied Phycology - Osmundea pinnatifida (Pepper Dulse) is a commercially interesting red alga harvested from the wild and sold dried as seasoning due to its distinctive peppery taste....     

The commercial potential of the common sea urchin Echinus esculentus from the west coast of Scotland

Sea urchin roe is a valuable food product. The commercial potential of Echinus esculentusL. (Echinodermata: Echinoidea) was assessed both by surveying field populations and gonad growth in response to artificial feeds. Urchins were collected from four locations on the Scottish west coast between June and August of 1998. The roe content was found to be of variable quality. A relatively low percentage of urchins (34.9%) had roe which was considered marketable both in terms of yield and colour. Urchins with a marketable yield of roe were found where algal growth or encrusting organisms were most prolific. Good roe colours and high roe yields were not necessarily coincident. The data suggest an urchin fishery is likely to be impractical economically. In tank-based trials large E. esculentus were fed either commercially available salmon feed, a pelletised urchin diet or the macroalgae Laminaria saccharina. Urchins fed the artificial diets increased in test diameter during the 24-week experiment. At the end of the trial urchins fed salmon feed had a significantly higher gonad and alimentary index than those in the other treatments. E. esculentusis able to successfully exploit a diet rich in animal-origin oils. The diets also influenced gonad colour. The proportion of urchins with marketable gonad colours was highest (85%) in the treatment receiving salmon feed. As this species appears robust in culture and as artificial diets promote somatic and gonadal growth, an investigation into the practicalities of a fully farmed approach to gonad production may be worthwhile.     

Abundance,structure, growth and origin of inshore clupeid populations of the west coast of Scotland

The abundance, structure, growth, and origin of clupeid populations in inshore waters of the west coast of Scotland were studied from April 1970 to October 1972. Clupeid populations in the area comprise mainly young fish. 0-group autumn-spawned herring, probably of Minch origin, move into the area about April and spring-spawned ones (Clyde origin) about June. The timing and the body length at which each group arrives in the area during the different years is the same. After the initial immigration, the distribution of both 0-group clupeids becomes localized.Herring populations in the sea-lochs and associated inshore waters are mainly 0-group fish, which are replaced each year by a new incoming brood. The sprat populations of the sea-lochs are dominated by the 0-group; in the more ‘open’ areas the populations comprise older individuals. Year-class distribution in the ‘open’ areas resemble that of the commercial fishery.The rate of increase of 0-group autumn-spawned herring is 3.68 mm/week and that of spring-spawned 0-group herring is 2.83 mm/week. The curves of growth of 0-group sprats of the 1970 and 1971 year-classes are different; the rate of increase in length, however, averages 3.55 mm/week for both year-classes and the differences are not significant.In sprats, after their first year of life a rapid increase in length takes place in the spring. This increase is thought to enable the majority of the population to reach the minimum size (88–90 mm) for initial gonadal maturation and thereby make them capable of reproducing in their second year of life.     

Two new species of free-living marine nematodes from the west coast of Scotland

Summary Two new species of free-living marine nematodes, found among the holdfasts of Laminaria saccharina off the West Coast of Scotland, are described. Bolbella gallanachmorae sp. nov. is characterized by a short gubernaculum and regularly curved spicules while Sabatiera scotlandia sp. nov. is characterized by long cervical setae, lightly built spicules with broad alae and a rather lightly built gubernaculum.

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Zusammenfassung Zwei neue Arten freilebender Nematoden, gefunden zwischen den Haftwurzeln von Laminaria saccharine an der Westküste Schottlands, werden beschrieben. Bolbella gallanchmorae sp. nov. ist durch ein kurzes Gubernaculum and regular gebogene Spiculi charakterisiert. Sabatiera scotlandia sp. nov. ist durch lange cervicale Borsten, leicht gebaute Spiculi mit breiten Alae, and ein ziemlich leicht gebautes Gubernaculum charakterisiert.

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Department of Zoology, British Museum (Natural History) (with 9 figs.)     

The fish populations in inshore waters of the west coast of Scotland. The food and feeding of the whiting (Merlangius merlangus L,.)

The food and feeding of the whiting ( Merlangius merlangus ) of the inshore waters and sea lochs of the west of Scotland were studied from 1969–1973. Fish and Crustacea were the main food items and their occurrence in the stomachs was clearly related to the size of the whiting and also to their seasonal abundance. The diurnal changes in feeding were also investigated and the results indicated that the size of fish was again an important factor which could affect the interpretation of the seasonal data.     

The genus Eurydice on the west coast of India

An ecological survey of the sandy beaches of the west coast of India revealed an important population of eurydicid isopods ( Eurydice peraticis Jones; E. indicis sp. nov.) of which one species is new to science. The systematics of these isopods are described, and their distribution on the Arabian Sea coast and the Indian beaches is discussed. Differences in their horizontal and vertical distribution on the beaches are explained in relation to the prevailing environmental conditions, of which exposure is the most important.     

Arenonemertes arenicolus sp.n. (Nemertea) from the Swedish west coast, with notes on the genus Arenonemertes

Arenonemertes arenicolus sp.n. is described from the Gullmar Fjord, Sweden. It differs from A. microps Friedrich, 1933 in: (1) lacking cephalic glands, (2) having an undivided caecum on the midgut, whereas the caecum is divided into three lobes in A. microps , and (3) the position of the nephridial ducts in relation to the lateral nerves (dorsal instead of ventral). Arenonemertes microps is still considered a valid species, but it is poorly described and the type material has been lost.     

Rett's syndrome in the west of Scotland.

Nineteen girls with characteristic features of Rett''s syndrome, including normal initial development, regression at about 12 months of age, repetitive hand movements, and severe mental handicap were studied. This represents an estimated incidence of one in 30 000 live births (one in 15 000 girls) in the west of Scotland. Although the children were often initially considered to be autistic, they did not conform to this diagnosis as they made good personal contact within the limits of their mental development. The developmental regression was sometimes falsely attributed to vaccination. Each child showed striking involuntary movements and abnormality of tone, varying from hypotonia, which was found only in the youngest, to rigidity, which was common in older girls; this permitted classification into three clinical subtypes. The abnormalities were highly suggestive of an extrapyramidal disorder, and this has implications for further research and possible treatment.     

The development of sessile epifaunal communities in Kylesalia,Kilkieran bay (west coast of Ireland)

Test panels, which were suspended horizontally at three sites in a shallow inlet on the west coast of Ireland, were sampled monthly over a period of one year to investigate the development of epifaunal communities. In addition, the current regime and sedimentation at these sites were measured. The deposited materials, of high organic value, may enhance the food supply to the sessile organisms through resuspension. Heavy deposition at one site interrupted the study. At the other two sites, however, the experiment was not affected. At one site, initial settlement by colonial bryozoans, followed by solitary ascidians, was noted on the panels over the period studied. In the competition for space, the dense aggregations during settlement, the relative large size, and the rapid growth of these solitary animals may occlude the colonization by colonial bryozoan mats underneath. At the other site, a more diversified community with co-existence of many sedentary polychaete and colonial bryozoan species was recorded on the panels. The continuing availability of free space on the panels suggests that the development of sessile communities at this site may be hindered by the relatively slow current flow and heavy deposition and resuspension. Whilst differences in community development were observed on the panels at these two sites, it would be difficult, through such a short study period, to ascertain whether stable climax states had been reached.     

The distribution, age and growth of wrasse (Labridae) in inshore waters of west Scotland

Wrasse were widely distributed in inshore waters of west Scotland in rocky and algal habitats. Ctenolabrus rupestris and Centrolabrus exoletus dominated commercial and experimental catches using creels, traps and fyke nets, but Crenilabrus melops, Labrus bergylta and L. mixtus were infrequent. Maximum age of sampled fish was 16yr in C. rupestris , 9 yr in C. exolefus , 5 yr in C. melops , 15 yr in L. bergylta , and 11 yr in L. mixtus . Growth was more rapid prior to maturation in all species. The von Bertalanffy growth model fitted data for C. rupestris and C. exoletus . Male C. rupestris and C. exoletus were significantly longer than females in most age groups and growth of all species captured in mid–Scottish areas was more rapid than in northern localities. Mortality (Z) of C. rupestris was 0–1861 per year and 0·4185 in C exoletus .     

Analysis of the cycle of reproduction of Sardina pilchardus (Walbaum, 1792) off the Moroccan Atlantic coast

This work focuses on aspects of reproductive biology of Sardina pilchardus from the Atlantic coast of Morocco. The mean values of batch fecundity estimated for the species is 23150(+/-1301) oocytes for a mean size of 19.5(+/-0.49) cm, the mean relative fecundity being 346(+/-7.34) oocytes per gram of female without ovary. Batch fecundity increases with total length and body weight without ovary. Sizes at first sexual maturity (L50) are reached for males and females at 15.8(+/-0.29) cm and 15.8(+/-0.35) cm, respectively. The spawning period for the population extends between October and July and the spawning peak occurs from October to February. However, the small sardines (14.5-17 cm) in their first reproduction spawn between November and June, whereas larger fish (17.5-25 cm) spawn between October and July. The factor of condition (K) increased in summer during the sexual resting phase. It is weak in winter during the period of reproduction. Regarding, the sex ratio, there was no significant difference in the number of males and females.