Upogebia Pusilla Research Articles

Response of deposit-feeders to exclusion of epibenthic predators in a Mediterranean intertidal flat

Deposit-feeders are common components of macrofaunal assemblages in intertidal soft sediments. Predation has been considered to have a central role in affecting their distribution and population dynamics. This study investigates the effect of epibenthic predators on deposit-feeders, inhabiting the shallow layers of the sediment (surface and subsurface) and also the deepest layers (e.g., burrowing shrimp Upogebia pusilla; Petagna). The experiment was conducted in summer 2000 (August–September) at three different sites on an intertidal flat in Mediterranean Sea. In the field, predators were excluded using cages, placed on the surface of the sediment. It was predicted that under the cages, (i) abundances of animals would increase and (ii) species composition of assemblages would change as an effect of the exclusion of predators. Potential artefacts caused by the cages were controlled using partial cages (PC). Composition of organic matter and porosity were also analysed under PC and in natural controls to test whether the presence of cages would change sediment characteristics on the surface. At the end of the experiment, there were no significant differences in the composition of organic matter between PC and the undisturbed sediment (UC). After 8 weeks from the beginning of the experiment, exclusion of predators enhanced the abundance of U. pusilla. There were, however, no clear-cut changes in the species composition of macrofaunal assemblages and densities of animals did not increase under the cages. Indeed, some animals (Oligochaeta, Brania oculata, and Tanais dulongii) were less abundant under the cages (EC) than outside (PC and UC). We propose that predation might play a role in regulating interspecific relationships among some surface deposit-feeders and the burrowing shrimp U. pusilla.

Redescription of the larval stages of Upobebia pusilla (Petagna, 1792) (Thalassinidea, Upogebiidae) from laboratory-reared material

Summary The complete larval development of Upogebia pusilla (Petagna, 1792) was reared under laboratory conditions and the development comprised four zoeal stages and a megalop. The morphological features were described, illustrated and compared with other known larvae of Upogebia.

Comparison of gut morphology and gut microflora of seven species of mud shrimp (Crustacea: Decapoda: Thalassinidea)

The gut morphology is described for seven species of Thalassinidea; Callianassasubterranea (Montagu), Jaxea nocturna Nardo, Axius stirhynchus Leach, Calocaris macandreae Bell, Upogebia pusilla (Petagna), U. deltaura (Leach) and U. stellata (Montagu). Differences were observed in the structure of the dorsal and lateral teeth of the gastric mill. Callianassa subterranea and A. stirhynchus had simple robust dorsal teeth and proportionally larger lateral teeth with flexible spines. The three upogebiids had complex dorsal teeth that were highly ridged and proportionally smaller lateral teeth with inflexible spines. The dorsal and lateral teeth of J. nocturna were intermediate in form. The dorsal tooth of Calocaris macandreae, although relatively simple in design, possessed accessory projections, or “wings”, on either side of the main structure. The lateral teeth were proportionally quite large, but lacked ridges and spines. The epithelia surfaces of the digestive gland, midgut and posterior diverticulum were similar for all seven species. Differences were observed in the morphology of the hindgut. The hindgut lining was completely smooth for the three upogebiid species. The other thalassinidean species had four distinct rows of cuticular projections situated on top of the ridges formed by the longitudinal convolutions of the hindgut. The arrangement of these projections varied between species. A gut flora was observed for six of the seven species, the exception being C. macandreae. The differences observed in the structure of the gut are discussed in relation to feeding and thalassinidean phylogeny.

Species and size selectivity in a ‘red’ sea bream longline ‘métier’ in the Algarve (southern Portugal)

A longline ‘metier’ using small hooks for ‘red’ sea breams ( Pagellus acarne and Pagellus erythrinus) in the Algarve (south of Portugal) was studied. Experimental longlining was carried out with three sizes of “Mustad” round bend, flatted, spade end Quality 2316 DT hooks (numbers 11, 13 and 15) and two types of bait: razor shell ( Ensis siliqua) and mud shrimp ( Upogebia pusilla). A total of 3 328 fish and at least 36 species were caught with 33 600 hooks fished in 28 longline sets. Five species of sea breams (Sparidae) accounted for 79% of the catch: Pagellus acarne, Pagellus erythrinus, Diplodus vulgaris, Spondyliosoma cantharus, and Boops boops. High catch rates of 20–30 fish per 100 hooks were made in a number of 1 200 hook longline sets, with total catch weights of 40 to more than 60 kg per set. In general, the smallest hook (number 15) had the highest catch rate. Bait type did not significantly affect the catch size distributions. Although more fish were caught with the razor shell bait, higher catch rates of ‘red’ sea breams were obtained with mud shrimp. Catch rates were also affected by the location of the fishing grounds and the time of the set, with the highest catch rates obtained when the longline was set within two hours before sunrise. A wide size range was caught for each species, with highly overlapped catch size frequency distributions for the three hook sizes used. Except for Spondyliosoma cantharus, few illegal-sized fish were caught, even with the smallest hook. The logistic model fitted by maximum likelihood was used to describe hook selectivity for Diplodus vulgaris, Pagellus acarne, Pagellus erythrinus, and Spondyliosoma cantharus.

Notes on Some Branchial Isopods Parasitic on Upogebiid Mud-Shrimps (Decapoda: Thalassinidea)

Bopyrids are highly modified epicaridean isopod ectoparasites with the adult females showing extreme specialization of body form when compared with free-living isopods (Shiino, 1965). The smaller males are similar to free-living isopods, retaining the basic cryptoniscus larval form (Naylor, 1972), and are typically found in the brood chamber of the female or attached to the ventral surface of the female's pleon (Salazar-Vallejo & Leija-Tristán, 1989).Whilst examining the branchial morphology of the upogebiids,Upogebia stellata(Montagu),Upogebia deltaura(Leach) andUpogebia pusilla(Petagna) as part of a wider study of the physiological ecology of thalassinidean mud-shrimps, some shrimps were observed to have a branchial gall (distended branchiostegite) containing a bopyrid parasite. In this short note we add to the previous records of two bopyrid species and briefly discuss the host/parasite relationship.Parasitized material examined:U. stellata(three males, two females) collected subtidally using an anchor dredge from White Bay, Isle of Cumbrae, Scotland (55°48'N 4°55'W) at depths of 25–30 m. A single male specimen ofU. deltaurawas caught using a box corer from the Irish Sea (54°7'N 3°27'W).Upogebia pusilla(one male, one female) were collected intertidally from the Arcachon Basin, France (44°40'N l°10'W) by Professor J.P. Truchot. Prior to examination, the mud-shrimps were preserved in 10% buffered formalin, the parasites removed, rinsed with distilled water and transferred to 70% ethanol. Some preserved material was also available from the Robertson Collection housed at the University Marine Biological Station Millport.Parasitized mud-shrimps had an enlarged branchial chamber, or branchial gall, a result of branchiostegite deformation caused by the presence of the parasite. When the parasite was removed from the branchial chamber, the gills appeared splayed and flattened but showed no other signs of disturbance or damage.

The Biology of Upogebia pusilla (PETAGNA) (Decapoda, Thalassinidea)

Abstract. Populations of the thalassinidean shrimp Upogebia pusilla were studied on tidal flats in the Northern Adriatic Sea. Biometric analysis showed a sexual dimorphism, especially in propodus size. Size frequency distributions revealed the presence of large animals during all seasons; recruitment by juveniles occurred in autumn. Moult intervals and moult increments were determined in the laboratory and used to generate growth curves which were compared with those calculated from size frequency distributions. The life span of U, pusilla is over 5 years. Ovigerous females occurred between March and September. Egg numbers were high in spring, lower in summer and increased with body size. The incubation time of embryos was 35 days; a female produces an estimated number of three egg batches during the breeding season. A total annual production of 994 kJ was estimated for a theoretical population of 100 animals; 13.5 % is spent for somatic growth, 31 % for egg production of females, and 55.2% is lost as exuviae. The population structures, growth and breeding patterns, as well as embryonic and larval development within the Upogebiidae and Callianassidae are discussed.

The Biology of Upogebia pusilla (PETAGNA) (Decapoda, Thalassinidea)

Abstract. The distribution of the thalassinidean shrimp Upogebia pusilla was studied at four sites in the North Adriatic Sea: 1) a tidal flat in the lagoon of Grado, 2) a tidal flat at Lido di Staranzano near the mouth of the Isonzo, 3) a mud flat seawards of a salt marsh in a protected bay north of Rovinj, and 4) a sublittoral station in 6m depth near Aurisina. Information on grain size distribution, organic content, amount of debris, redox profiles and pH of sediment as well as temperature and salinity is given. Density, as determined by hole counts and a hole: burrow relationship derived from resin casting, generally increased with increasing water depth in the intertidal. The upper limits ranged between +10cm (Rovinj) and ‐20cm (Grado); densities between mean water and low water level varied strongly due to microtopography and macrophyte cover. Maximum densities in the intertidal ranged from 189 (Grado) to 2420 (Rovinj, juveniles) animals m2. Shrimp density at the sublittoral station ranged between 80 and 230 m“2. The zonation of the Upogebiidae and Callianassidae with respect to environmental parameters is discussed.

The Biology of Upogebia pusilla (Petagna) (Decapoda, Thalassinidea) I. The Burrows

Abstract. The biology of the thalassinidean shrimp Upogebia pusilla was studied on a tidal flat in the Lagoon of Grado (Northern Adriatic). Burrows were investigated using in situ resin casting and with additional in situ and laboratory observations. Burrows show a basic pattern consisting of a U or a double U with turning chambers and a vertical shaft. Mean burrow diameter depends on animal size, it is smaller than the rigid carapace of the animal. Dimensions, distance between openings, depth of U, total depth, volume and surface are size dependent. The burrow wall is smooth and oxidized. Burrows are always inhabited by a single shrimp. Although they overlap, they are never interconnected. They are mainly constructed by compression of the sediment and are relatively permanent structures. A comparison of the burrows of Thalassinidea with regard to shape, number and appearance of openings, dimensions, properties of the burrow wall and dynamics is given.

The pumping rates of the burrowing shrimp Upogebia pusilla (Petagna) (Decapoda:Thalassinidea)

The pumping rates of the burrowing shrimp Upogebia pusilla (Petagna) were measured with an overflow apparatus. Short-term pumping rates were correlated with cube of animal size and ranged from 0.004 to 0.89 ml/s. These rates, along with a mean pumping time of 28% as determined by respiration measurements, gave long-term rates ranging from 5 to 900 ml/h. The water exchange through the burrows of the total U. pusilla population in the lagoon of Grado is compared with the exchange of water with the open sea due to tides.

Gravity anomalies in Gulf of California : Harrison J.C. and S.P. Mathur, 1964. In: Marine geology of the Gulf of California, a symposium, Amer. Ass. Petrol. Geol., Memoir (Edited by van Andel T. and George G. Shor Jr.), 3: 76–89

In marine sediments, cages are widely used to detect effects of predation on infauna. Artifacts due to the use of cages have been, instead, poorly estimated. In this study we have analysed the changes in macrofauna and in sediment composition when cages of different mesh sizes are used to exclude predators. In a shallow micro-tidal flat, the effect of three mesh sizes (2, 6 and 18 mm) was tested on sediment and macrofauna, using cages that excluded predators (EC), partial cages (PC) and natural sediment (un-caged plots, UC). PC allowed the predators to feed on the sediment, but modified the sediment similarly to the complete cages. Changes were measured for the abundance and species composition of macrofauna and for sediment total organic matter (TOM), chlorophyll-a, proteins and water content.The use of cages did not alter TOM and water content, whereas chlorophyll-a and phaeopigments were more abundant under the cages. The deep-burrowing shrimp Upogebia pusilla also increased under cages of any mesh-size. There was, instead, an effect on the abundance of macrofauna only when the smallest mesh size was used. Surprisingly, the exclusion of predators decreased the abundances of Tanais dulongii, Oligochaetes, Brania oculata, whereas the abundance of Aphelochaeta marionii changed when both PC and EC were put in the sediment. Collectively, all these findings indicated that for surface animals the use of small mesh sizes can bias the interpretation of results.