Colin G. Moore

The occurrence of intersexuality in harpacticoid copepods and its relationship with pollution

Abstract Intersexuality in harpacticoid copepods is extremely rare, only one specimen having previously been recorded in the literature over 40 years ago. We record the presence of intersexes of several species in the Firth of Forth and elsewhere in Scotland. The possibility that pollution may be implicated in the causation of the phenomenon is suggested by the high level of intersexuality in the vicinity of a major sewage discharge off Edinburgh, where 93% of the specimens examined of one of the dominant species exhibit intersexuality.

Intersexuality in benthic harpacticoid copepods in the Firth of Forth, Scotland

Following the discovery of a high frequency of intersexuality in Paramphiascella hyperborea in the vicinity of Edinburghs long-sea sewage outfall, the seabed off the Edinburgh coast was surveyed in spring and autumn to examine the distribution of intersexuality in relation to the sewage outfall. From these and previously collected samples it was found that intersexuality was common in both P. hyperborea and Stenhelia gibba and also present in two species of Halectinosoma. Intersexuality was widespread along the Edinburgh coastline, being recorded up to 10 km from the discharge but there was no evidence for a correlation between intersex frequency and proximity to the discharge. Possible reasons for the high level on intersexuality in the Firth of Forth are discussed. Most intersexes displayed similar secondary sexual characters, with the sexually dimorphic prosome appendages taking the female form, the 5th leg intermediate between male and female and the 6th leg and urosome segmentation male in character.

The status and ecology of reefs of Serpula vermicularis L. (Polychaeta: Serpulidae) in Scotland

1. The distribution and abundance of reefs of Serpula vermicularis was examined in Loch Creran, the only known remaining site of reefs of this species in Scotland. In view of the decline in populations elsewhere, the aims included assessment of the importance of the Scottish population in terms of conservation of the reef habitat and the establishment of a baseline against which future changes could be gauged. A further objective was to determine appropriate conservation management of the reefs by examining the influence of both natural and anthropogenic factors. 2. Reefs were largely restricted to a depth range of 1–13 m. Factors controlling the depth distribution are discussed. 3. Serpula vermicularis reefs colonized a variety of substrata, but predominantly grew on lamellibranch shells on a seabed of muddy sand. There was some evidence that reef abundance was influenced by the availability of suitable substrata. 4. A belt of scattered reefs fringed much of the coastline of the loch with profuse reef development at two sites, where reef coverage exceeded 10% of the seabed. In terms of total abundance of Serpula vermicularis reefs, Loch Creran represents the major world site for reef development. It is concluded that the reefs of Loch Creran are of significant nature conservation importance and grounds for the establishment of conservation management are discussed. 5. Reef development is apparently curtailed in areas of strong currents and high flushing rate. There is evidence that human activity has adversely influenced reef growth through the discharge of organic factory effluent and the physical disturbance caused by mooring ground tackle. Scallop dredging also represents a significant threat to the persistence of serpulid reefs. Methods of minimising damage to this rare and fragile feature are discussed.

Rearing dover sole larvae onTisbe andArtemia diets

The suitability of the harpacticoid copepodTisbe holothuriae as a diet for larval and juvenile Dover sole (Solea solea) was assessed by rearing groups of sole for 42 days under a range of dietary regimes. Larval sole, approximately 1 week old, were reared onTisbe, Artemia, or a mixedTisbe-Artemia diet for 13 days. No significant differences in length between sole larvae from any diet were found after this time, but larvae offeredArtemia alone showed a significantly higher frequency of malpigmentation than those offered the other diets. After metamorphosis (day 16), survivors of this experiment were reared for a further 29 days on various diets to give the following dietary sequences:Tisbe-fed larvae, fed onArtemia as juveniles (Tis.-Art.);Artemia-fed larvae, fed onArtemia as juveniles (Art.-Art.);Artemia-fed larvae, fed onTisbe as juveniles (Art.-Tis.) and mixed diet fed larvae, fed on a mixed diet as juveniles (AT-AT). At the end of this period AT-AT and Tis.-Art.-fed juveniles were significantly larger than those on the Art.-Art. dietary regime. Juveniles from the Tis.-Art. dietary regime consumed more prey items than the Art.-Art group. AT-AT juveniles consumed similar amounts of food to Art.-Art. juveniles but were significantly larger after 29 days culture. This was attributed to the presence ofTisbe in their diet. Overall, the best larval and juvenile diet appeared to be a mixed diet throughout the culture period.

The impact of Melinna palmata grube, a tube-building polychaete, on meiofaunal community structure in a soft-bottom subtidal habitat

Abstract Field investigations were performed in a low-energy subtidal muddy sediment in Loch Creran, a sea-loch on the west coast of Scotland where the impact of Melinna palmata , a tube-building polychaete, on the meiofaunal community structure was assessed. This polychaete was found in high densities and forms prominent faecal casts on the sediment surface. Samples were retrieved from the casts, the feeding area of the polychaete and from an unaffected control area. The number of nematodes, the dominant taxon, did not vary significantly between areas. Of the five most abundant nematode species one was significantly more abundant in the cast area. Diversity and trophic structure of the nematode component of the meiofauna was very similar in all three areas. Copepods were more than twice as abundant in background sediments as in faecal mounds and feeding areas; however, Longipedia spp. were more abundant in the cast areas. For the copepods these findings support models which state that natural disturbances create a mosaic of patches that have different species compositions depending on their states of recovery.

The taxonomy and biology of a new species Pontonema (Nematoda, Oncholaimidae) dominant in organically polluted sublittoral sediments around Scotland, with a review of the genus

A new species of free living marine nematode, Pontonema alaeospicula sp. nov., is a dominant member of the fauna in three organically polluted sublittoral habitats off the Scottish coast. The species is described and the genus reviewed. A schematic pictorial key to the genus is provided. Some notes on the biology of P. alaeospicula sp. nov. are given, based on initial studies of the population in situ and in laboratory culture.

Community composition and diversity of two Limaria hians (Mollusca: Limacea) beds on the west coast of Scotland

Limaria hians functions as a keystone species in construction of a highly diverse biogenic habitat. An investigation to quantify the biodiversity of two L. hians beds was carried out during the winter and summer seasons at two sites on the west coast of Scotland. Cores were taken semi-randomly through 100% L. hians nest material, organisms removed, identified and enumerated. Univariate and multivariate analyses of the data were used to establish temporal and locational differences. A total of 7275 individuals were found representing 282 species from 16 phyla. Univariate analysis revealed significant differences between the species richness of the two populations, whilst multivariate analysis illustrated differences in the assemblage compositions between sites and times. This study showed that in terms of richness and diversity these beds are among the most important biogenic habitats in the UK.

A re-examination of some problematical species of Haloschizopera (Copepoda, Harpacticoida)

Haloschizopera material was examined from 64 sublittoral sites around Britain and Ireland and several additional locations around the world. Although unrecorded since 1906, H. pygmaea was found to be a dominant species around Great Britain. It is redescribed and synonymized with H. junodi. H. mathoi is widely distributed in the Mediterranean basin but has hitherto been recorded under different names. It is redescribed and synonymized with H. pontarchis.

A review of the harpacticoid genus Paraleptastacus (Crustacea, Copepoda)

Summary The sympatric occurrence of three species of Paraleptastacus on Port Erin Beach and elsewhere around the Isle of Man provided the opportunity to study the comparative morphology and variability of the species. All three species, P. spinicauda, P. espinulatus and P. holsaiicus, were found to be easily distinguishable when Manx specimens were compared with each other and with previous descriptions. The diagnoses of the genus and these three species are amended, the validity of other species in the genus discussed and a new key constructed for each sex.

A new species of Halectinosoma (Copepoda, Harpacticoida) from the Isle of Man

Summary A new species of Halectinosoma Lang, 1948, H. pterinum sp. nov. is described from the Isle of Man. Examination of this and some other species of the genus under high magnifications suggests that the diagnosis of the genus may have to be modified.