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The swimming actions and performances of young green turtles ( Chelonia mydas ) and freshwater chelonians of similar size ( Mauremys caspica, Chrysemys scripta elegans and Kinosternon subrubrum ) were compared to evaluate the advantages conferred by the hypertrophied flapping forelimbs and streamlined form of the marine species. Evidence is presented to demonstrate that propulsive force is generated both on the upstroke and the downstroke of the green turtle’s foreflippers, and that the force is produced largely by hydrodynamic lift generated as the flippers move through the water at relatively modest angles of attack. The green turtle’s forelimbs therefore act like wings rather than as oars or paddles. Specimens of Chelonia mydas can generate twice the propulsive force, and swam six times as fast as Mauremys caspica . Much of this advantage stems from the efficiency of the swimming action (much less negative thrust is generated by C. mydas than by M. caspica ) together with the streamlined shape, which also permits effective gliding. The swimming performance of young green turtles is similar in efficiency to that of streamlined fish such as mackerel.

Environmental temperature is a controlling factor in ecology and is influenced by global climate change. Upper/lower thermal limits for 10 species of sessile/sedentary invertebrates were established on a single rocky shore. Two species with different reproductive strategies (Littorina littorea, Nucella lapillus) from 3 Scottish and 3 Irish shores were investigated to test effects of small scale (<10 km) or larger scale (ca. 500 km) distances, and shore height on upper lethal temperature. At 3 sheltered and 3 exposed shores in Ireland, thermal responses of N. lapillus from the middle of their vertical distribution were compared. Amongst the 10 species from a single shore, thermal niche width rose asymptotically with maximum height of distribution on the shore and maximum emersion time. Median upper lethal temperature and median lower lethal temperature were closely correlated. For 8 species on the middle and upper shore, there were significant linear relationships between shore height and the variables upper lethal temperature, lower lethal temperature and thermal niche width. L. littorea upper lethal temperature was found not to vary with shore height, varied little over small geographical distances, but was significantly higher in Ireland than in Scotland. N. lapillus upper lethal temperature was higher in animals collected from the upper limit of distribution on the shore than in dogwhelks from the lower limit of distribution, was higher in animals taken from sheltered shores than from exposed shores and showed significant local differences. Upper lethal temperature was higher in Scottish than Irish dogwhelks. KEY WORDS: Thermal niche · Intertidal invertebrates · Littorina · NucellaResale or republication not permitted without written consent of the publisher

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Coelenteron contents of anemones Actinia equina collected from 2 shore heights (upper and lower) on 3 shores (exposed, semi-exposed and sheltered) in south-west Ireland were investigated in summer 2009. Diets of exposed and semi-exposed shore anemones were dominated by small mussels Mytilus edulis, mostly (> 90%) with broken/cracked shells. The diet of anemones on the sheltered shore was dominated by insects, particularly on the upper shore. On all shores, larger food items (isopods, mussels, insects) were broken or fragmented; only small gammarid amphipods, crab megalopae, midges and mosquitos were found whole. Laboratory behavioural experiments showed that A. equina were unselective at small prey size, but were limited by their own size, which restricted the maximum size of prey that could be ingested. Whole mussels were ingested, but egested alive after mean elapsed times of 0.75 to 1.95 h (depending upon anemone size). In contrast, mussels with cut adductor muscles, and incapable of shell valve closure, were fully digested, empty shells not being egested until 8.70 to 8.95 h after ingestion. Whole, live mealworms Tenebrio molitor were eaten by anemones, but were egested after a mean 1.30 h with no signs of digestion or fragmentation. Mealworms with mechanically perforated exoskeletons were held in the coelenterons of A. equina for a mean of 5.90 h and all soft tissues were digested. It was concluded that A. equina predominantly scavenges on macrofaunal carrion, as well as preying upon smaller food items.