0ebe157e4d8dbe8cc38820a3f548c64d English dataset Carly Cassidy University Marine Biological Station (UMBS), Millport Millport KA28 0EG carlycassidy@hotmail.co.uk pointOfContact 2019-11-04 MEDIN Discovery metadata standard 2.3.8 4326 1998 UMBSM Clyde Sea The Ecology of Juvenile Lumpsuckers 1998-01-01 publication 1995-11-07 creation 1995-11-07 revision UMBSM9497 A PhD was carried out at the University Marine Biological Station Millport (UMBSM) and submitted to the University of London. "Life in floating weed: the ecology of juvenile lumpsuckers Cyclopterus lumpus L." The PhD investigated the diet of juvenile C.lumpus, the energetic costs of swimming versus sucker attachment and aimed to investigate factors which influence C.lumpus behavioural associations and interactions with floating weed. Data Manager Universtity Biological Station, Millport University Marine Biological Station (UMBS), Millport Data Manager Millport KA28 0EG dassh.enquires@mba.ac.uk originator Kathryn Stevenson University Marine Biological Station (UMBS), Millport Millport KA28 0EG kathryn.stevenson@millport.gla.ac.uk custodian notPlanned Documents Marine Environmental Data and Information Network Species distribution GEMET - INSPIRE themes, version 1.0 2008-01-06 revision Fish behaviour SeaDataNet P021 parameter discovery vocabulary 2009-11-16 revision The contents of the study may not be reproduced unless the source of the material is indicated. otherRestrictions DASSH terms and conditions apply (https://www.dassh.ac.uk/terms-and-conditions) English biota -5.0070 -4.8615 55.7209 55.8021 1994-04-01 1995-11-07 Data Archive for Seabed Species and Habitats (DASSH) Data Manager 01752 633102 01752 633291 Marine Biological Association of the UK, The Laboratory, Citadel Hill Plymouth PL1 2PB dassh.enquiries@mba.ac.uk distributor dataset The PhD is divided into a series of topics and investigations. Firstly, the macrofaunas of floating weed patches and those of weed free surface waters was compared in the Firth of Clyde and the Firth of Lorne. Both sampling sites are on the west coast of Scotland. A neutson net was designed to be efficient at the collection of floating weeds. A net was designed using a lightweight pre-holed steel angle (Dexion) frame and stramin nets, which were 2m in length and had a mesh size of 2mm. The net was constructed with outriggers which held two 25 litre plastic barrels which were used as floats. The top 0.30m of water was sampled. Sampling aimed at obtaining juvenile lumpsuckers from floating weed patches and was conducted on board R.V. Aplysia (UMBSM) in the Firth of Clyde and on board R.V. Seol Mara, in the Firth of Lorne. Firth of Clyde sampling was conducted during April 1994 - March 1995. Firth of Lorne sampling was conducted during January 1995 - December 1995. Sampling targeted areas where floating weed was in a high concentration. Visual observation determined whether floating weed was present at the primary sites in both study areas (Garroch Head in the Firth of Clyde and Ardmucknish Bay (north) in the Firth of Lorne). If floating weed was absent, the secondary sites (Keppel Bight and Tolmont End; Oban Bay and Loch Etive) in both locations was visited. Sampling was conducted fortnightly however discrepancies are apparent due to adverse weather conditions or vessel unavailability. All sampling was conducted between 0900 and 1500 GMT. Tow times varied considerably (15-240 minutes) with hauls having tow times ranging from 10 to 30 minutes in duration. The amount of weed recovered ranged from 0-100kg. Sub-samples were obtained from the larger sample sizes. Fish located in the macrofaunal samples were placed into a plastic beaker and anesthetized using a benzocaine solution. The remaining macrofaunal sample was poured through a 0.05mm mesh sieve and transferred to a 1 litre plastic jar. Samples were then fixed in 8 percent formalin/seawater solution. Anesthetized fish were transferred to the macrofauna sample by hand net. All macrofauna samples were washed and preserved in 70 percent alcohol within 24-48 hours of fixation. Weed free neuston samples were conducted post weed sampling. The neuston net was cleaned by being towed for 5 minutes with the cod-end opened. Once cleaned, cod-ends were closed and the neuston net was towed for 15 minutes. The sample was recovered and transferred to a 1 litre plastic jar and fixed in 8 percent formalin/seawater solution. The weight of any weed (if present) was determined within the laboratory. All macrofaunal samples were sorted, enumerated and identified to species. Data is displayed in semi-quantitatively form due to inaccuracies in tow distance and due to using sub-samples. The seasonal occurrence and size distribution of juvenile lumpsuckers from surface and bottom habitats in both study areas and their relationship to growth was investigated. Data from this investigation pools the data obtained from all juvenile lumpsuckers which were obtained during the full duration of the study. The majority of lumpsuckers were obtained from floating weed in both study areas. Sublittoral samples were also taken when floating weed was absent and occasionally when weed was present. A few samples were also collected from floating rafts which were moored in the Firth of Lorne during the period of May-September 1995. All sizes are standard length which is measured from the snout to the posterior edge of the caudal peduncle. No systematic sampling of larval or adult lumpsuckers was undertaken during the study however some larvae were obtained by the sampling gears due to clogging by weed samples. Adults were obtained by beam trawl and records were supplemented by SCUBA observations. Size distribution of juvenile lumpsuckers is based on samples from the neuston net and supplemented from samples obtained from the dipnet used during the investigation which was utilised to compare the diet of juvenile lumpsuckers with macrofauna. Dip net samples were also taken to provide live material for laboratory studies. Sublittoral sampling was conducted using a small beam trawl which was towed from the research vessels. The beam trawl had a beam with a length of 1.5m and was positioned 0.75m above the skids. The beam net was 2m in length and the mesh graduated from 25mm at the net mouth and 2mm at the cod-end. the majoirty of sampling was undertaken at primary sites (Brigurd Spit in the Firth of Clyde; Dunstaffnage Bay in the Firth of Lorne). Secondary sites (Fairlie Channel and Kames Bay; Ardmucknish Bay (south) and Tralee Bay) were used as alternatives during adverse weather. primary stations ranged from 4-8m in depth and were characterised by a mixture of coarse sand, gravel, cobbles and boulders which provided a suitable substratum for kelp. The beam trawl brought the kelp habitat to the surface for sorting. Moored floating rafts were also sampled in Dunstaffnage Bay by dipnet. Floating rafts were the floating walkways of redundant salmon cages with the nets removed. The data referring to the growth of juvenile lumpsuckers is based on wild-caught, aquarium-reared, juvenile lumpsuckers which were caught in the Firth of Lorne. Animals were maintained in the laboratory and kept at an ambient temperature of 14-17 degrees Celsius and with a light regime of 12 hours light/ 12 hours dark in flow-through aquaria. the temperature of the aquaria was approximately 1 degrees Celsius above the neighbouring sea. Animals had a constant supply of live food. Initially animals were fed upon mixed zooplankton which was caught daily in Dunstaffnage Bay. Once grown to an acceptable size, animals were fed on mysids (Neomysis integer and Praunus flexuosus) collected from Dunstaffnage Bay also. Standard length and total length were recorded to the nearest 0.5mm once a week and the wet weight was measured to the nearest 0.01g. Growth of lumpsuckers was monitored over 96 days from the date of capture (1 June 1995). An overall mortality of 14 percent was identified over the 96 days as animal declined from 42 individuals to 36. The diet of juvenile lumpsuckers from both study sites was investigated. Diet was determined by stomach content analysis. Juvenile lumpsuckers from surface waters were provided from the samples from the weed sampling study stated earlier. Sublittoral juveniles that were utilised were obtained from the beam trawl samples. A preliminary investigation into the diet of juvenile lumpsuckers from the Firth of Lorne suggested that the stomach contents were predominantly composed of discreet prey items. A numerical approach to analysis was conducted to appropriately describe the diet of juveniles. Examination of stomach contents was performed on preserved animals. A Wild M5 binocular microscpe with a magnification of x6-25 was used for examination purposes. The microscope was illuminated by transmitted and reflected cold light sources (Schott KL1500 electronic). Specimens were placed into a Petri dish with 70 percent alcohol and examined. Standard length of the fish was recorded to the nearest 0.5mm using a plastic ruler. All other measurements were obtained and recorded using a microscope eyepiece graticule. The gape width of the fish was measured by inserting a fine needle into the mouth. Dissection was carried out by use of a scalpel, fine forceps and sharp tungsten wire needles. The alimentary tract was removed once the abdominal cavity was opened. this was achieved by severing the pharynx at the distal end of the intestine. The stomach was then separated from the alimentary tract. A scale of 0-4 (empty-full) was attained to assess the fullness of stomach. the stomach was carefully opened and the stomach contents was analysed. Prey (diet) was identified to the lowest taxonomic group which was feasibly possible and enumerated. The maximum body dimensions (excluding appendages) of prey was recorded for sample sizes of 20. Prey preference was expressed by using the following formulas: percentage occurrence equals the Number of stomachs that contained prey type divided by Total number of stomachs examined multiplied by 100 and relative importance equals the Total number of prey type divided by the Total number of all prey. The study also compared the diet of juvenile lumpsuckers with that of macrofauna of discrete samples of floating weed. Discrete floating weed samples were collected using a fine mesh dipnet. Samples were fished by hand from a small dinghy. The dipnet measured 20cm x 20cm with a mesh plankton net (142 microns in aperture) with a 0.5 litre plastic jar attached to the cod-end of the net. Samples were back-washed with seawater into 1 litre plastic jars and fixed in 8 percent formalin/seawater solution. Samples were collected between May and August from both study sites. Samples were washed into a 142 micron sieve and seaweed was removed and wet weighed. The standard length, gape width and stomach fullness were recorded for each juvenile lumpsucker and processed as stated earlier. Macrofaunal density was expressed as individuals 1 (to the power of -1). Macrofaunal components were identified to the lowest taxonomic level, enumerated and the maximum body dimension measured for 20 individuals of each taxon/developmental stage. The taxonomic composition of the diet of juveniles and the macrofauna were expressed as percentage frequency of each prey type/faunal component. Nine component categories were established: calanoid copepods, harpacticoid copepods, cyclopoid copepods, amphipods, isopods, brachyuran zoeae, brachyuran megalopae, crustaceans miscellaneous and fish. each component was assigned to a category. Size compositions are displayed as percentage frequency of size groups within a range. The oxygen consumption of juvenile lumpsuckers was investigated for two different activity levels. The activities investigated were continuous swimming and attachment by sucker. A respirometer was used to assess oxygen consumption. Specimens were caught off Kepple Bight by dipnet. Observations of individuals within a closed chamber identified that lumpsuckers preferred to attach to the internal surfaces of the chamber. Swimming was rare and only for short durations. As swimming was identified as not a voluntary activity within a closed container, it was not possible to measure oxygen consumption rates at both levels of activity by simply determining which particular activity mode corresponded with oxygen consumption. A separate respirometry chamber for each activity was therefore utilised. A closed chamber was adopted for both activities. The first chamber (used for sucker activity) consisted of a 500ml straight sided polypropene screw top jar. A plastic boss on the inside surface of the base of the jar contained a magnetic follower which was constrained by a plastic mesh cover. The corresponding boss on the outer surface enabled the chamber to be located on a submersible magnetic stirrer. A hole in the centre of the lid enabled the oxygen electrode (radiometer type E5046 oxygen electrode) to pass into the chamber. A rubber grommet created a tight seal. The chamber designed for the swimming activity were similar, except all inner surfaces were lined with plastic mesh to prevent lumpsucker attachment. A single plastic mesh cage lined the lid and oxygen electrode. A plastic paddle with a magnetic flea was attached by a wire spindle through the centre of the base of mesh sleeve which masked the electrode. The magnetic stirrer caused the plastic paddle to sweep the entire base of the chamber and agitated the water. This encouraged fish to swim. The chambers comprised of an insulated water bath (Grant Y38 water bath) filled with fresh tap water which was maintained at a constant temperature by the interplay between a cooler (Grant CK2 cooler) and a thermostat heater (Grant KD temperature control unit). Equipment contained within the water bath were an acclimation vessel, which was a 5 litre plastic aquarium, filled with fine filtered seawater (using a 2 micron - Millipore filter) and continuously aerated. A submersible magnetic stirrer (rank Brothers Ltd) was also present. Chambers were located on the magnetic stirrer unit. The oxygen electrode was connected to an acid-base analyser (Radiometer type PHM71 Mk2 Acid- base analyser). The analyser was connected to a flat-bed chart recorder (Rikadenki model R-22 electronic recorder). Experiments were carried out over a 50 day period from 1994-11-03 to 1994-12-21. Fish were maintained at ambient temperature with a natural light/dark regime in a flow-through aquaria. Specimens were fed once daily on live amphipods (Gammarus locusta). At the beginning of experiments the acclimation vessel was filled with fine filtered seawater which was pre-cooled to 10 degrees Celsius and the temperature was allowed to equilibrate. The oxygen electrode was calibrated. The analyser and chart recorder were adjusted to read zero when the oxygen electrode was immersed in filtered seawater de-aerated with oxygen-free nitrogen. the electrode was then placed in the acclimation bath containing air saturated filtered seawater. The sensitivity of the chart recorder was adjusted to give near full scale deflection. A respirometer was ran with no fish present for an hour. Fish were starved for 48 hours prior to experimentation and transferred to the acclimation vessel 1 hour before the experiment. Experiments were carried out at 10 degrees Celsius and at a salinity of 32 parts per thousand. The respirometer is assembled under the surface of the acclimation vessel and the fish was coaxed in. The sealed respirometer was located on the magnetic stirrer and oxygen depletion was recorded. Each experiment included 1 fish and lasted for 1 hour. At the end of experiments the equipment was washed in a mild solution of sodium hypochlorite. During the study an experiment was conducted to investigate habitat selection by juvenile lumpsuckers. sample individuals were caught off Dunstaffnage Bay using a dipnet. Experiments were carried out in a 60 x 36 x 30cm glass aquarium. Activity was video cassette recorded using a time lapse video cassette recorder (Panasonic model AG 6730) set to 12 hour recording mode. A camera (Vista NCD372 12v mono video camera) and a lens (Vista VZB880A 8-80mm F1.8 auto-iris zoom lens) were mounted on a tripod to view the aquarium. Experiments consisted of a number of trials, each lasting 1 hour. The position and activity of experimental individuals were recorded in each frame (50min) of each trial. The vertical position of the aquarium was designated upper, middle or lower zone. The activity mode of the juvenile lumpsucker was noted and surface attachment was recorded. Experimental fish were divided into four groups dependent on their standard length range at capture (mm). Group A were used in Experiment 1. Group B were used i Experiments 2 and 3 and groups C and D were used in most experiments. There were 6 habitat choice experiments. They involved introducing a juvenile lumpsucker into an aquarium which had a range of plastic structures present. The structures were constructed of 100mm diameter x 10mm deep lids from 500ml jars. Two horizontal lines were marked on the back of the tank to indicate the vertical position of the fish. Experiments were also conducted to determine the habitat selection of juvenile lumpsuckers at different levels of feeding motivation and predation risk. The aquaria for such experiments was divided into three compartments with transparent Perspex baffles which had a series of 12mm diameter holes and an air stone in the vertical compartment. The lower horizontal compartment housed a predator (single juvenile cod (Gadus morhua), 162mm standard length). The lumpsucker was confined to the upper horizontal compartment. A closed container within the aquaria enabled mysids to be present however they were unavailable to the lumpsucker. Each experiment was performed at two levels of feeding saturation, fed and hungry. Hungry fish were starved for a minimum of 4 days. The objective of such experiments were to establish the concept that feeding activity is correlated with the need to minimise predation.