John D. Booth

Early Life History of Spiny Lobster

Spiny (rock) lobsters are the basis of important fisheries in all of the worlds major oceans. We synthesize current information on their early life history from a variety of biological disciplines and draw conclusions about the significance of this phase in the ecology of the group. Larval behaviour is still poorly understood and the scale of larval dispersal conjectural. However, recruitment processes in some shallow-water species, including effects of the environment on these processes, are becoming clearer. Field and laboratory studies have increased our understanding of phyllosoma larval development and behaviour. Our knowledge of the puerulus stage has increased dramatically, particularly concerning behaviour from studies using collectors to measure settlement and through laboratory experiment. Discovery of the habitat of young juveniles has led to examination of relationships between puerulus abundance at sea, levels of puerulus settlement, and the abundance of juveniles and recruits.

Jasus edwardsii larval recruitment off the east coast of New Zealand

Geographic differences in levels of Jasus edwardsii puerulus settlement on the east coast of New Zealand during the 1980s were associated with differences in abundance offshore of mid- and late-stage phyllosoma larvae and with water flow patterns. Levels of puerulus settlement on crevice collectors and abundance of phyllosomas in plankton samples were greatest off the North Island south of about East Cape. The pattern of phyllosoma abundance appeared to be determined by factors which included levels of local larval production and the oceanography. Phyllosomas occurred almost exclusively seaward of the continental slope while most pueruli were caught on the shelf. Some phyllosomas reached final stage about 12 months after the spring hatching, but often metamorphosis to the puerulus stage and settlement did not take place until the following summer to spring; this gives an oceanic development period of 12-24 months. Settlement seasons have been generally consistent over time scales of 1-3 decades. Most commonly, settlement is in winter, but the main settlement seasons vary according to locality, nearby sites having similar seasons except over particular stretches of coastline where seasons change radically. Reasons for the seasonal pattern in settlement are unknown. Year to year levels of settlement were correlated at widespread sites, showing that factors which drive larval recruitment may influence large areas in a similar way at the time.

Size at the onset of sexual maturity in female Jasus edwardsii (Decapoda: Palinuridae) in New Zealand

The size at the onset of sexual maturity for female rock lobsters, Jasus edwardsii, was defined as the size or size class at which 50% of the rock lobsters in a sample were mature, and was estimated at 27 localities around New Zealand. Animals were regarded as mature if they were bearing external eggs attached to the pleopods or if there were well developed setae on the endopodites of the pleopods. Samples from the same location in different years showed little variation in the size at the onset of maturity. There was, however, considerable variation between localities, ranging from 72 mm carapace length near Gisborne to 121 mm carapace length in eastern Foveaux Strait. Size at the onset of maturity showed an inverse relationship with water temperature. The relationship between the size at the onset of maturity, age, growth rate, and water temperature is discussed.

Settlement of the red rock lobster, Jasus edwardsii, near Gisborne, New Zealand

Abstract A collector monitored the settlement of the puerulus stage of Jasus edwardsii near Gisborne during 1980–82. Details of the construction, deployment, and checking of the collector are given. The main peak of settlement occurred during winter, when catch rates averaged over a set of 3 collectors reached 0.9 puerulus per collector per day. There was evidence for a much smaller peak during summer. Puerulus settling during winter were significantly larger than those settling at other times of the year. The highest number of animals on an individual collector was 18. The collector may prove useful in providing an index of natural settlement.

Comparative Morphology of the Mouthparts and Foregut of the Final-Stage Phyllosoma, Puerulus, and Postpuerulus of the Rock Lobster Jasus Edwardsii (Decapoda: Palinuridae)

ABSTRACT The gross morphology and fine structure of the mouthparts and foregut of the rock lobster Jasus edwardsii were studied in its late larval and early juvenile stages. The stage-XI phyllosoma has third maxillipeds with specialized setae, second maxillipeds and first maxillae with strong setae, mandibles with well-developed molar and canine-like processes and teeth, and a foregut with well-developed grooves and brushes but no gastric teeth. The first-molt juvenile has third and second maxillipeds and first maxillae with rows or tufts of numerous strong setae, wellcalcified mandibles with strong molar and incisor processes, and a foregut with well-developed ossicles, grooves, brushes, and strong gastric teeth. In contrast, the puerulus has maxillipeds and maxillae with only small numbers of setae, uncalcified mandibles with a rudimentary incisor, and a foregut with a small number of ossicles and setae, and rudimentary lateral teeth. These observations suggest that the late-stage phyllosoma of J. edwardsii feeds primarily on large, soft materials and the early postpuerulus on hard, as well as soft, materials. In contrast, the puerulus probably does not feed during some or all of its existence, and any feeding is on small, soft materials. Use of nutrients stored in the digestive gland is one possible way that the puerulus could meet its energy requirements.

Genetic subdivision of Australian and New Zealand populations of Jasus verreauxi (Decapoda: Palinuridae)—preliminary evidence from the mitochondrial genome

Abstract The palinurid rock lobster, Jasus verreauxi, has a disjunct distribution, occurring on the east coast of Australia and in New Zealand. Oceanic currents flowing across the Tasman Sea from Australia towards New Zealand and the long life of phyllosoma larvae suggests larval mixing and, consequently, genetic similarity between these populations. However, restriction endonuclease analysis of the mitochondrial DNA (mtDNA) of 25 late juvenile and adult lobsters showed that Australian and New Zealand haplotype assemblages are defined by two restriction sites, one confined to each locality. Genetic differentiation between Australian and New Zealand J. verreauxi was also supported by gene diversity analysis (GST). In contrast to the results from a similar study of a congeneric species with an analogous distribution (J. edwardsii), these preliminary results suggest that larval exchange between adult populations across the Tasman Sea may be limited.

Review: Diverse larval recruitment strategies within the Scyllaridae

Abstract Scyllarid lobsters, together with the palinurids, have a long‐lived, planktonic phyllosoma larval phase in their early life history followed by a much briefer postlarval phase which at settlement completes the planktonic period of their life cycle. Information on scyllarid larval biology and recruitment mechanisms is fragmentary. Scyllarid species exhibit a wide range of larval recruitment strategies and durations, from entire larval and postlarval phases being completed in just a few weeks within lagoons, through to species that become widely dispersed in ocean basins over many months. In contrast, the phyllosomas of all palinurids so far investigated invariably, over many months, become widely dispersed in the open ocean well beyond the continental shelf. Among scyllarid species a general relationship is apparent between adult size and the extent of larval dispersal. During the planktonic period currents, in combination with larval vertical migratory behaviour, probably play an important role in larval dispersal and return. Although varying greatly in size, the postlarval nisto of most scyllarids appears to be similar in behaviour to the puerulus of palinurids. Nistos are usually (if not always) non‐feeding and appear to alternate between swimming at night and resting on the bottom during the day as they move inshore to regain adult grounds before settling and metamorphosing to the first juvenile lobster instar. Those scyllarids with a somewhat abbreviated larval duration and mainly coastal larval distribution—the “flat” species of Ibacus and Thenus—appear to have succeeded in exploiting local currents and biotic systems to restrict larval dispersal and maintain their place. Based on the characteristics of the larvae and their recruitment mechanisms, there is support for the present division of the Scyllaridae into its four subfamilies, but also backing for revision, particularly of the Ibacinae.

Application of yield models to the New Zealand rock lobster fishery

Two general types of yield model, stock production and dynamic pool (yield‐per‐recruit), were used to analyse available data for the New Zealand rock lobster, Jasus edwardsii (Hutton). An exponential stock production model was applied to commercial catch and effort data from 1945 to 1975 for the North and South Islands combined. The results suggest a maximum sustainable yield of 4227 t with an estimated optimal level of fishing effort of 784 vessels, about 60% of the 1975 number. Empirical and von Bertalanffy growth equations were derived from limited tag‐recapture data from the Gisborne area. Both equations indicate that males grow faster than females. The empirical growth equation, based on moult increment and frequency as functions of size, is considered the more realistic. Two yield‐per‐recruit models provided different results, especially at low levels of natural and fishing mortality. One model (Beverton‐Holt) incorporated the von Bertalanffy growth equation and the other (empirical model) an empiri...

Measuring depth of settlement in the red rock lobster, Jasus edwardsii

Abstract Settlement of the puerulus stage of Jasus edwardsii (Decapoda: Palinuridae) near the shore takes place over a wide depth range. It occurs intertidally, and, as determined by crevice collectors, also takes place down to depths of at least 50 m. At sites along the east coast of the North Island of New Zealand, depth of greatest settlement found on collectors varied with locality and time, but was within the upper 11.5 m. Surface‐buoyed collectors caught fewer animals than did collectors at greater depths. Settlement levels generally increased with depth to about 10–12 m, then decreased with increasing depth and distance from shore. The ability of/, edwardsii to settle over a wide depth range may improve its chances of recruitment. A device (closing crevice collector) for measuring puerulus settlement of J. edwardsii at depth is described.

Puerulus and juvenile abundance in the rock lobster Jasus edwardsii at Stewart Island, New Zealand (Note)

Abstract Settlement of puerulus‐stage New Zealand red rock lobsters (Jasus edwardsii) and abundance of the first three juvenile cohorts were measured from 1981 to 1989 near Halfmoon Bay, Stewart Island. Puerulus settlement on subtidal collectors shows great annual variation. Juvenile abundance, estimated from the number caught in annual diver collections, shows less variation. One‐year‐olds appear less vulnerable to diver sampling than older juveniles. Abundance of 2‐ and 3‐year‐olds is highly correlated with puerulus settlement 2 and 3 years previously. Survival between puerulus and 1+ stages appears to be density‐dependent, but survival of older juveniles does not. Size is inversely related to abundance in 3+ females but not in the other cohorts, suggesting density‐dependent growth between ages 2 and 3. Puerulus settlement rates and processes on shallow inshore reefs appear to be important in determining recruitment strength in this species.