VOLUME SIXTEEN MARCH 2003 NUMBER ONE ANNOUNCEMENTS The 7th International Conference and Workshop on Lobster Biology and Management will be held in Hobart, Tasmania from the 8 – 13 February 2004. Since the last conference in Florida in 2000 new challenges have emerged for scientists, managers and industry. Co-management and cooperative research is seen as the future model for managing the world’s marine resources. Ecosystem based management has refocused research into meta-population studies including marine protected areas and ecosystem modeling. Incorporation of environmental and socio-economic performance indicators is a requirement for a new generation of fishery management plans. Record high prices have also attracted interest in aquaculture and enhancement. Meeting these challenges has resulted in significant advances in the methods used to study lobster resources. This conference will provide the opportunity for researchers and managers with an interest in lobsters to meet, discuss and learn of these new and exciting advances. More information can be found at the conference website: www.cdesign.com.au/lobster2004 Please pass on this address onto your colleagues who may be interested in attending. We plan to put the program together early in 2003 and would welcome any suggestions regarding themes or sessions. We also welcome offers for hosting the 8th International Conference. If you are interested please contact Stewart Frusher at [email protected] or write to Stewart Frusher, Marine Research Laboratories, Tasmanian Aquaculture and Fisheries Institute, University of Tasmania, Private Bag 53, Hobart, 7001,Tasmania, Australia. The Lobster Newsletter - Volume 16, Number 1: March 2003 1 VOLUME SIXTEEN MARCH 2003 NUMBER ONE FISHERIES & comparison of the ecological and economic efficiency of trammel net and trap fisheries in the Balearic AQUACULTURE UPDATE Islands (Quetglas et al., in preparation), catchability in traps and trammel nets (Goñi et.al, in press), bycatch and discard practices in Mediterranean artisanal fisheries (Mas et al., in preparation), and Threats to the sustainability of reproductive biology and spawning potential of a Palinurus elephas fisheries protected population (Goñi et al., submitted). The regulatory framework From: Raquel Goñi, Antoni Quetglas, No quotas exist in P. elephas fisheries and reliable Olga Reñones and Javier Mas catch statistics are not available. In the Spanish Mediterranean effort controls and technical measures Palinurus elephas is the most commercially important are used to manage fisheries. Fishing effort is spiny lobster species in the Mediterranean and regulated by an annual 6-month closure during the North-eastern Atlantic. Known as “red lobster” in the egg-bearing period (September to February) and Western Mediterranean and as “crayfish” in the there are caps on the amount of gear fished per boat North-eastern Atlantic, P. elephas has been (5000 m trammel nets) and on the soak time (<48 traditionally targeted by artisanal fisheries hours). The minimum mesh size of the trammel net throughout its range. Customarily, lobster were outer and inner panels and the maximum size of the caught with baited traps until the 1960-1970s when traps are also regulated. Finally, it is forbidden to trammel nets were introduced, leading to the virtual land lobster smaller than 80 mm CL (about 4 years) disappearance of trap fishing. Concomitantly, fishing and berried females. effort increased and populations in the NE Atlantic where depleted to the point that it is now a bycatch Despite this multiplicity of regulations, the reality is species of finfish netting. Although Mediterranean that effort limits are not enforced -boats may have up populations are thought to be overfished, they are to 10000 m of trammel nets that are fished still targeted in many areas, especially in remote simultaneously through the season of which they areas such as archipelagos and islands. In the may haul 2000-3000 m per day - and nets may be Spanish Mediterranean, over six hundred artisanal soaked 3 or more days. This state of affairs is vessels and some 1100 fishermen engage in lobster aggravated by the unpredictability in the number of fishing with trammel nets every year. A relict trap boats among those with license for artisanal fishing fishery exists in the Balearic Islands. The annual that will fish for lobster during any given season, the economic value of the fishery in Spain has been dispersion of the fleet in many small harbours along estimated at 8-16 million euro (first sale). the coast and that landings are often sold directly to restaurants. In these circumstances, the temporal The history of depletion of P. elephas populations has closure and the fishermen’s acceptance that prompted a study to assess the main threats to the immature and berried lobsters should be returned to sustainability of these fisheries with the aim of the water, remain the only practical controls in the incorporating this knowledge to the management of Spanish fishery (as in other Mediterranean fisheries). Spanish Mediterranean fisheries. We are looking into four aspects of lobster fishing: the regulatory The minimum landing size framework, the adequacy of the minimum landing Observations onboard fishing vessels suggest that it size for protecting the reproductive potential of the is common practice to release undersized specimens populations, the current exploitation pattern and the when they are freed from the net in good condition potential impacts of trammel net fishing on lobster (condition depends on season, water temperature, habitats. For this analysis we use data from various and soak time among other factors). Undersized recent and ongoing studies of P. elephas: a lobsters in trap fisheries are usually caught and The Lobster Newsletter - Volume 16, Number 1: March 2003 2 VOLUME SIXTEEN MARCH 2003 NUMBER ONE released in good condition. Islands Marine Reserve, the study concluded that the exploitation pattern of the females would be similar Knowing the wide acceptance of this measure, our in trap and trammel net fisheries, while the interest was to determine the biological basis and exploitation pattern of the male component would adequacy of the 80 mm CL minimum landing size differ. Thus it may be inferred that large males (MLS) to protect the spawning potential of the would be more abundant in populations fished with population. The current MLS was set on the basis of traps than in populations fished with trammel nets. empirical observations of berried females and a study of the reproductive biology of Western Mediterranean populations indicated that the mean 20 18 size of functional maturity was 77-78 mm CL (Goñi FEMALES 16 et al., submitted). The same study showed that if an 14 Trammelnet, n= 372 unfished population were to be harvested, a MLS of 12 Trap, n= 420 80 mm CL would protect only 12% of the catchable % 10 8 population and 1% of the population potential egg 6 production (Fig. 1). The same study suggests that a 4 MLS of 87 mm CL or 92 mm CL would allow 2 lobsters to reproduce once or twice before being 0 susceptible to fishing. The larger of the two MLS 12 would afford protection to 25% of the population MALES potential egg production. 10 Trap, n= 338 8 Trammelnet, n= 393 20 % 6 18 Females 16 4 RRP 14 12 2 % 10 0 8 40 50 60 70 80 90 100 110 120 130 140 150 160 170 Figure 2: Size structure of feCmL (amlme)s and males fished with 6 traps and trammel nets from the protected population of P. 4 2 elephas in the Columbretes Islands Marine Reserve. 0 40 50 60 70 80 90 100 110 120 130 140 In the Spanish Mediterranean, no P. elephas CL (mm) population exists that is solely fished by traps and Figure 1: Female size structure and relative reproductive thus it is not possible to verify these predictions. potential of the P. elephas population from the Columbretes However, when we compared size distributions of Islands Marine Reserve. MLS: Minimum landing size. RRP: trammel net catches from various fished populations Relative reproductive potential. with those from the protected population in the reserve, we observed that the unfished population Exploitation pattern contained a greater proportion of large males than Our investigations on the catchability and selectivity exploited populations (Fig. 3). As predicted, the size of traps and trammel nets for P. elephas (Goñi et al., structure of females did not differ between the fished in press) indicated that, from the point of view of and unfished populations. conservation, traps were preferable to trammel nets because they retained a smaller proportion of Sustainability of P. elephas exploited populations are juveniles and because the largest lobsters (mostly difficult to assess in full. However, the decline in the males) were either too large to enter traps or were availability of large males for mating in exploited able to feed without entering (Fig. 2). On the basis of populations may result in loss of reproductive the size structures of trap and trammel net catches of the protected population of the Columbretes The Lobster Newsletter - Volume 16, Number 1: March 2003 3 VOLUME SIXTEEN MARCH 2003 NUMBER ONE potential of the population to an extent formerly generate bycatch, much of which is made up of attributed only to large females. Thus the change in finfish, molluscs and crustacean commercial species exploitation pattern brought about by the that are increasingly relied upon to supplement substitution of traps by trammel nets in all P. elephas dwindling lobster yields. But while 66% of the fisheries may be one of the causes of their demise. individuals caught by traps are lobsters, in trammel net catches this proportion declines to 43% if the non- 40 commercial benthos - bryozoans, sponges, algae, RM Columbretes 35 FEMALES Levante echinoderms, etc- is excluded from the calculation. 30 Placer However, in an attempt to assess more Menorca 25 comprehensively the impacts of lobster fishing on Mallorca %20 benthic ecosystems, we devised an arbitrary method 15 of “counting” the bycatch of these taxonomic groups, 10 which often are not taken into consideration in 5 bycatch/discard studies. Thus we “counted” all 0 algae and bryozoans “units”, sponges, echinoderms, tunicates, annelids, etc. and added them to the finfish, macrocrustacean and macromollusc bycatch. 30 RM Columbretes Then we used two indicators of the ecological impact 25 MALES Levante Placer of fishing (Alverson & Hughes 1996): (a) the “lobster 20 Menorca ecological use efficiency” (LEUE) – or number of Mallorca % 15 lobster caught divided by the number of all organisms caught, and (b) the “fishery ecological use 10 efficiency” (FEUE) – or number of lobster and other 5 commercialised bycatch caught divided by the total 0 number of organisms caught. 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 CL (mm) Figure 3: Size structure of trammelnet catches in fished 1.0 (various Western Mediterranean fisheries) and unfished TRAPS 0.9 (Columbretes Islands Marine Reserve) populations of P. 0.8 NETS elephas. 0.7 NETS-BENTHOS 0.6 0.5 The implications of the pattern of exploitation of 0.4 trammel nets for the sustainability of P. elephas 0.3 exploited populations are difficult to assess in full. 0.2 However, the decline in the availability of large 0.1 males for mating in exploited populations may result 0.0 in loss of reproductive potential of the population to LEUE FEUE an extent formerly attributed only to large females. Thus the change in exploitation pattern brought Figure 4: Indices of performance of traps and trammelnet about by the substitution of traps by trammel nets in lobster fisheries in the Western Mediterranean. See text. all P. elephas fisheries may be one of the causes of their demise. Using these more comprehensive indices we learned that in traps lobster still made up 61% of the catch (in Impacts of trammel net fishing on lobster habitats number) while in trammel nets lobster made up only The causes of the collapse of Atlantic P. elephas 1.4% of the catch (in number) (Fig. 4). When fisheries and of the depleted status of Mediterranean considering the efficiency of the fishery as a whole ones may also be sought in the differential impacts of (that is, not only lobster but all the commercialised trammel net and trap fishing on lobster habitats. catch), the ecological efficiency of the trap fishery Both traps and trammel nets The Lobster Newsletter - Volume 16, Number 1: March 2003 4 VOLUME SIXTEEN MARCH 2003 NUMBER ONE rose to 97% while that of the trammel net fishery Meeting the environmental requirements of a species reached only 1.8%. Close examination of the throughout its larval development is paramount to taxonomic composition of the benthos-bycatch reveals successful propagation. In rock lobsters, accurate a large fraction of structural species such as coralline definition of environmental preferences is and incrusting algae (Maërl), bryozoans, or sponges complicated by the complex and prolonged larval characteristic of lobster habitats. Some of these development. Like other crustacean larvae, the species have very slow growth rates. growth of phyllosomas (Fig. 1) is incremental and takes place at the moult through a series of instars The results of the studies here summarized point to (up to 17; Kittaka 1994) and 11 developmental stages major problems in the management and exploitation (Lesser 1978). The first difficulty arises from possible scheme of Palinurus elephas fisheries that can be shifts in environmental preference during larval traced to the introduction of trammelnets and to the development, since in the wild, phyllosomas migrate increased fishing effort associated with between such distinctly different environments as technological advances in materials, hauling gear coastal and oceanic waters. A second, less obvious and positioning systems occurred in recent decades. difficulty is the manner in which nutritional needs Further research will focus on developing are met, with phyllosomas accumulating reserves performance indices, both ecological and economic, and then drawing on them to continue development of the fisheries to provide operative advice for the under sub-optimal conditions (Mikami et al. 1995). sustainability of P. elephas fisheries. Thus, for a given developmental stage, the effect of culture conditions will be biased (accentuated or Raquel Goñi, Antoni Quetglas, Olga Reñones lessened) by the environmental and/or nutritional and Javier Mas history of the larva. Centro Oceanografico de Baleares Muelle de Poniente s/n Aptdo 291 \ Palma de Mallorica 07080 Spain [email protected] LITERATURE CITED Alverson, D.L. & S.E. Hughes (1996). Rev. Fish. Biol. Fish., 6: 443-462. Goñi, R., Quetglas, A., & Reñones, O. (in press). Fish. Res. Larval culture of the Southern Rock Lobster (Jasus edwardsii) Figure 1: Stage I southern rock lobster phyllosoma in From: Michel Bermudes flight. The idea of the project was to study each early As part of ongoing research into rock lobster phyllosoma stage independently, and for each to propagation supported by the Australian Fisheries obtain a snapshot of behaviour and physiology Research and Development Corporation (Rock under different environmental conditions. This Lobster Enhancement and Aquaculture could lead to an ability to control larval distribution Subprogram), I recently completed a PhD on the in tanks and thus maximise space and food use. A larval biology of J. edwardsii in Tasmania. Here is a powerful performance index, where: summary of my study. The Lobster Newsletter - Volume 16, Number 1: March 2003 5 VOLUME SIXTEEN MARCH 2003 NUMBER ONE potential growth = energy intake – energy output continuous darkness (Fig. 4), it is thought that rock lobster larvae use the light phase for feeding while could be derived experimentally for each the dark phase is used for food assimilation. It is developmental stage, independent of the previous therefore recommended that phyllosomas be fed at environmental and/or nutritional history (Fig. 2). the start of the day, and uneaten food flushed out at night. seawater inlet seawater outlet nger 0.25 o-ring ) y a d 0.20 icnhcaumbbaetrio n m/ m freshwater outlet ( 0.15 water jacket e screen at r h 0.10 freshwater inlet stirring flea wt o r O2 electrode G 0.05 0.00 10 12 14 16 18 20 22 magnetic stirrer Temperature (°C) Figure 3: The effect of temperature on the growth rate of Figure 2. Schematic view of experimental apparatus used stage I larvae. to measure the oxygen consumption (energy expenditure) of stage I larvae. 0.088 Not surprisingly, temperature was found to be an important factor controlling development in early y) 0.084 a phyllosomas (Fig. 3). Maximum growth rates were d m/ 0.080 achieved at 18 - 19°C, the reduced performance at m ( higher temperatures being due to the energetic e 0.076 at imbalance between food intake and metabolic h r expenditure. wt 0.072 o Gr 0.068 Light was the predominant cue controlling behaviour, as larvae were less active in the dark 0.064 than under light. Low light intensities (~ full moon, dark light light/dark dusk, dawn) may be used to optimise larval Photoperiod distribution in tanks and therefore maximise density. Greater activity of larvae under light Figure 4: The effect of photoperiod on the growth rate of caused higher energy expenditure than in the dark. larvae reared from stage I to stage IV. The light/dark However, larvae under light fed more than their photoperiod was 18 h of daylight to 6 h of dark. counterparts in the dark, thus maximising energy use. Since the growth of phyllosomas was higher Part of this project addressed the water quality under a simulated natural photoperiod (18L:6D requirements of phyllosomas – a topic for which there and 12L:12D) than under constant light and is little information. As would be expected for a The Lobster Newsletter - Volume 16, Number 1: March 2003 6 VOLUME SIXTEEN MARCH 2003 NUMBER ONE largely oceanic animal adapted to a clean and stable environment, phyllosomas require consistent water Mothers know best ! Artificial quality, particularly in terms of salinity (optimum incubation of spiny lobster eggs around 34 - 35 psu) and dissolved oxygen (must be over 80% saturation). However, larvae appear well From: Phil James adapted to recirculation systems since they tolerate ammonia concentrations up to ~ 0.1 mg NH -N l-1, 3 and so are similar to molluscs and other crustaceans As part of the spiny lobster broodstock programme, (Forteath 1990). researchers at the NIWA Aquaculture Research Facility in Wellington tested the feasibility of Research into rock lobster propagation is a step by removing fertilized eggs from females and hatching step process them in incubators. This is a technique that could This study provided information on the give much greater control over when and at what environmental requirements of early stage rate eggs hatch. Currently, numerous eggs (up to 1.4 phyllosomas. Similar work is now required for later million) are hatched over a very short period (2 – 4 d) stages. The methods developed in this project are from each female to supply phyllosomas for research. powerful tools for defining larval culture conditions If it were possible to detach the eggs and keep them for these more advanced larval stages, and also for in incubators, a more constant supply could be larvae of other lobster species currently being available by controlling temperature and consequent evaluated in Australia, Japan and New Zealand. egg development (Tong et al 2000). Our previous Fine-tuning of the system design and culture research has shown that egg hatch times can be techniques is a key to the successful propagation of spread over four months by manipulating the the southern rock lobster, which will be achieved temperature in the holding tanks – and with little through the thorough understanding of the loss of viability. environmental requirements of phyllosomas. There were two experiments. For both, the eggs were LITERATURE CITED removed by running a scalpel around the edge of the pleopod, severing the setae, and gently removing the Forteath, N. (1990). A handbook on recirculating eggs. The eggs remained attached to the setae systems for aquatic organisms. Fishing Industry throughout as there is no way to separate them Training Board of Tasmania Inc., Hobart, without damage. Australia. Kittaka, J. (1994). Pp. 402-423 In: Phillips, B.F., Cobb, The first experiment used eggs at various stages of J.S. and Kittaka, J. (eds), Spiny Lobster development from different gravid Jasus edwardsii (n Management. Blackwell Scientific Publications, = 42) in a recirculating system. There were 56 Oxford. incubators (Fig. 1), each holding 74 ml of seawater Lesser, J.H.R. (1978). N.Z. J. M. Freshw. Res. 12: 357- and with 1.37 l.m-1 of water upwelling through a 450 370. µm sieve. A 3 g egg sample from each lobster was Mikami, S., Greenwood, J.G. and Gillepsie, N.C. soaked in a 1‰ formalin solution for 1 min prior to (1995). Crustaceana 68: 160-169. the experiment. The remaining eggs were left attached to the females as a control and the females Michel Bermudes returned to the holding tank. After 5 weeks, mass School of Aquaculture, Tasmanian Aquaculture and mortality of the eggs in all the incubators had Fisheries Institute occurred due to an infection by an invasive Nubeena Crescent – Taroona 7053 – Tasmania oomycete, later identified by DNA sequencing as AUSTRALIA Haliphthoros sp. An unidentified species of [email protected] Haliphthoros had previously been found on samples taken from puerulus and juvenile J. edwardsii The Lobster Newsletter - Volume 16, Number 1: March 2003 7 VOLUME SIXTEEN MARCH 2003 NUMBER ONE (Diggles 2001). None of the control eggs were To test the effectiveness of chemical treatment for affected by fungi and they hatched normally. controlling pathogens, some eggs from three Sagmariasus (formerly Jasus) verreauxi were removed and treated with formalin, as above. A 10 g egg mass was placed in each of the incubators which were then randomly assigned one of two treatments: either the eggs were left in the incubators without any chemical treatment; or the eggs were given a 1 h bath, three times a week, using 0.5 ml l-1 of ‘Malcon’, a zinc-free malachite green oxalate. The egg masses on the females were again controls. All eggs in the second experiment, regardless of treatment, became infected by a solid, white, blanketing layer of bacteria. Twelve species of bacteria were present but it was not possible to isolate those causing the egg mortality. Only 39% of the incubators had any phyllosomas hatch and in only 28% of these did more than 1% of the eggs Figure 1: Detail of incubators used in the first spiny hatch. Of this 28%, 11% hatched from incubators lobster egg experiment. that were treated with Malcon and 17% from incubators that did not receive any chemical In the second experiment the flow-through system treatment. The eggs that were retained on two of the consisted of 18 glass salmon ova incubators (Fig. 2) female lobsters as controls hatched normally placed in a 2 m x 0.8 m fiberglass trough. Each without any bacterial problems whilst the third incubator was supplied with filtered (2 µm) female stripped her remaining eggs. seawater (1.6 l m-1) through a vertical inlet pipe. Despite the upwelling motion, the eggs formed clumps in both incubators, an ideal breeding ground for both bacteria and fungi. It seems the grooming and fanning by the female is critical in maintaining the health of the egg mass and these actions cannot be replicated by the upwelling systems and chemical cleaning such as those used in the experiments. The results also indicate that there is a suite of infectious organisms present in the egg mass – once the eggs are removed from the female they opportunistically proliferate. When one organism is removed, the next dominates, as was the case in the second experiment when fungi were removed and bacteria took over. Their small size and associated pathogenic fauna mean that spiny lobster eggs do not readily lend themselves to being removed and held in incubators. Mother lobsters know best! Figure 2: Glass salmon ova incubators used in the second spiny lobster egg experiment. The Lobster Newsletter - Volume 16, Number 1: March 2003 8 VOLUME SIXTEEN MARCH 2003 NUMBER ONE LITERATURE CITED behavior of P. guttatus, because this species is an Diggles, B.K. (2001) J. Fish Dis. 24: 99-110. obligate reef-dweller that spends long times Tong, L.J., Moss, G.A., Pickering, T.D. and Paewai, within its shelters, in contrast to P. argus, which is M.P. (2000) Mar. Freshw. Res. 51: 243-248. highly mobile and has several ontogenetic habitat shifts. Phil James NIWA First, we studied the shelter-related behavior of Private Bag 14-901 groups of six individually marked P. guttatus Wellington through several observational series. We focused on NEW ZEALAND their daily activity rhythms and their behavioral [email protected] patterns as related to shelter occupancy. Observations were conducted in outdoor circular tanks 3 m in diameter, provided with artificial shelters that resembled a triple-chambered reef cave. RESEARCH NEWS Each chamber was equipped with a closed-circuit video camera that recorded the activity of lobsters inside the shelters (Fig. 1). The tapes were later processed in the lab. One of ELA’s students, Iris Behavior of spiny lobsters inside Segura-García (2001) reported on parts of this communal shelters: the “Big Brother” information in her thesis. approach From: Enrique Lozano-Álvarez, Patricia Briones-Fourzán and Howard M. Weiss Many species of spiny lobsters are gregarious and shelter communally. Most field or laboratory behavioral studies on spiny lobsters, including their social behavior, have been conducted outside their shelters, i.e., when the lobsters leave their shelters to Figure 1: Diagram of the experimental system. carry out their daily activities (reviews in Atema & Cobb, 1980; Herrnkind, 1980). However, the In-shelter activity of the groups of P. guttatus behavior of spiny lobsters inside their communal occurred both day and night, increasing at 05:00– shelters has seldom been reported. We recently 06:00 h —prior to dawn— and decreasing during the started a series of short-term studies on the in- day. Out-of-shelter activity occurred solely at night shelter behavior of two spiny lobster species, but peaked at 20:00–21:00 h, whereas shelter Panulirus argus and P. guttatus, using an approach occupancy was 100% from 06:00 to 18:00 h. Lobsters akin to the “Big Brother” devised by George Orwell tended to aggregate in the shelters and to climb to in his book “1984”. We used artificial caves the walls rather than staying on the floor of the caves. equipped with video cameras that “observe” and Thirty-two different behavioral units (most of them record the activity of lobsters within the cave. Our described for other spiny lobster species by Atema & first attempts, conducted in artificial caves deployed Cobb, 1980), grouped in six categories, were recorded in tanks, included the recording of a group of and their frequency measured over one night. Results lobsters of both species and one predator (the indicate that individuals of P. guttatus (a) are rather triggerfish Balistes vetula) (Lozano-Álvarez & reclusive and do not leave their shelters during the Briones-Fourzán, 2001), and of several groups of P. day; (b) are more gregarious than solitary; and (c) argus cohabiting with moray eels (unpublished). In maintain a high level of in-shelter activity, with 2000 we also began systematic studies on the evidence suggesting dominance by large males. The Lobster Newsletter - Volume 16, Number 1: March 2003 9 VOLUME SIXTEEN MARCH 2003 NUMBER ONE We are currently using one-chambered artificial Lozano-Álvarez, E. & P. Briones-Fourzán. 2001. Mar. caves deployed directly on a natural shallow Freshwat. Res. 52: 1145–1155. seagrass meadow at Puerto Morelos, Mexico, Segura-García, I.H. 2001. Thesis, Universidad designed for behavioral studies on large juvenile P. Nacional Autónoma de México. 49 pp. argus. We have used these shelters in two different series. In the first series, four individual P. argus Enrique Lozano-Álvarez & Patricia Briones-Fourzán were tethered so that they could roam the cave Unidad Académica Puerto Morelos, Instituto de Ciencias freely but could not escape from it. In the second del Mar y Limnología, UNAM. series, the lobsters were untethered, but the cave P.O. Box 1152, Cancún, Q. R., 77500 México was modified with funnel-shaped entrances that [email protected] allowed other organisms to enter but precluded the [email protected] four lobsters from leaving the shelter. Although Howard M. Weiss both series were preliminary, they yielded Project Oceanology, interesting data. Despite the continuous presence of Avery Point, Groton, CT 06340 USA the lobsters, a suite of mobile organisms entered the [email protected] artificial caves, in particular moray eels (Gymnothorax moringa and G. vicinus) and other lobsters. In our previous observations in tanks, In ovo embryonic development of the lobsters and moray eels cohabited in the caves for up to 17 days without aggressive interactions. Mediterranean slipper lobster, However, in one of the caves deployed on the Scyllarides latus seagrass meadow, one G. moringa readily fed on the corpse of a lobster that had been previously killed (presumably by a transient triggerfish). On a From: M.L. Bianchini and S. Ragonese different occasion, a moray eel entered the cave several times, explored it, killed and consumed a The Mediterranean slipper lobster, Scyllarides latus live lobster, and left the cave. The whole sequence of Latreille 1803, quite common until the 1970s, is now events lasted a mere seven minutes. a rare occurrence in Italian water. Therefore, a feasibility study on stock enhancement was carried Because lobsters other than the “forced residents” out a few years ago (Bianchini et al., 1998). While the have also occupied the artificial caves on the complete larval development has been achieved seagrass meadow, we are considering the under artifical conditions in various Scyllaridae deployment of empty artificial caves and waiting for species, only a few stages are known for the genus free lobsters to colonize them. This could yield less Scyllarides (Robertson, 1969). In S. latus, only the manipulated observations. The “Big Brother” early free-swimming larvae have been described approach could be a useful tool to analyze the in- (Santucci, 1925; Santucci, 1928; al-Kholy, 1981; shelter behavior of different species of lobsters, Glavic et al., 2001), and none for in ovo embryonic especially those which, as P. guttatus, remain in their development. shelters for long periods. The Mediterranean slipper lobster (whose sex-ratio is 1:1) mature, copulate, spawn and brood easily in LITERATURE CITED aquarium conditions, although fertilization of the roe mass is often incomplete. In our tanks, the Atema, J. & J. S. Cobb. 1980. Pp. 409–450 In The smallest berried female was 491 g (mean 783 g). Of Biology and Management of Lobsters, Vol 1. about 100 “appropriately-sized" females handled Academic Press, New York. during the study, 40% of the specimens were Herrnkind, W. F. 1980. Pp. 349–407 In The Biology and captured already berried or matured in the Management of Lobsters, Vol 1. Academic Press, laboratory tanks. This species does not necessarily New York. molt prior to mating. The Lobster Newsletter - Volume 16, Number 1: March 2003 10