Paratya Curvirostris Research Articles

Acute and sub-chronic effects of sub-lethal cadmium exposure on energy metabolism in the freshwater shrimp, Paratya curvirostris

Cadmium (Cd) is a toxic trace element enriched in waters through activities such as mining and agriculture. The freshwater shrimp Paratya curvirostris inhabits near-coastal, lowland streams potentially impacted by Cd, but nothing is known regarding its sensitivity to this metal. An acute (96h) median lethal concentration (LC50) of 405µgL−1 was derived for P. curvirostris, placing it among the most tolerant of freshwater shrimp species. Acute (4 d; 0, 50 and 100µgL−1) and sub-chronic (10 d; 0, 25 and 50µgL−1) exposures then investigated effects of Cd on energy metabolism (respiration rate, excretion rate, O:N ratio). In contrast to effects in previously studied species, Cd induced an increased respiration rate, which when coupled with an unchanged excretion rate, resulted in an increased O:N ratio. These data were explained by an increased reliance on carbohydrate and/or lipid as a metabolic substrate stimulated by increased metabolic costs of toxicant exposure. Similar effects were seen across all time-points, although the lowest effective Cd concentration decreased with increased exposure time. Overall, results suggest that Cd is unlikely to be a significant environmental stressor to P. curvirostris, except in highly contaminated freshwaters, and/or where Cd co-occurs with hypoxia.

Learning the ropes: mussel spat ropes improve fish and shrimp passage through culverts

Summary Culvert pipes are regularly used around the world for conveying stream flows underground, through embankments or under road crossings. Installation of these features can have significant negative effects on the passage of freshwater biota and potentially exclude many species from large areas of river networks. We investigated the installation of mussel spat ropes as a potentially rapid and cost‐effective tool for improving passage of freshwater biota through culvert pipes where internal barrel conditions impede passage. We assessed passage success for two fish species, juvenile rainbow trout Oncorhynchus mykiss (Walbaum 1972) and adult inanga Galaxias maculatus (Jenyns 1842), and one migratory shrimp, Paratya curvirostris (Heller 1862), through culverts of differing length (3 and 6 m), slope (1·5 and 3°) and flow (0·24 and 0·75 L s−1). We hypothesized that ropes would enhance the passage success of these three species, but success rates would differ between species and trial combinations. Ropes resulted in a reduced water velocity within culvert barrels and significantly improved passage success for all three species. Shrimp benefited most by the presence of ropes, being unable to negotiate any of the pipe combinations in their absence, but exhibiting varying rates of success across all combinations with their presence. Both G. maculatus and O. mykiss were able to negotiate some of the non‐roped pipe combinations, but as the level of difficulty increased, successful passage was only achieved with the ropes present. Synthesis and applications. We conclude that this relatively inexpensive and easy‐to‐install tool has the potential to substantially improve passage for a range of aquatic biota through various culvert scenarios. We consider that ropes would be particularly useful in situations where internal culvert access is difficult and where various culvert parameters (slope, flow, length) result in internal barrel hydraulics that would normally limit or exclude passage of aquatic biota.

Conservation breeding of Shortfin eels Anguilla australis and Giant kokopu Galaxias argenteus at Mahurangi Technical Institute using aquarium and aquaculture techniques

Mahurangi Technical Institute (MTI) operates a commercial fish hatchery that conducts aquaculture research, acts as a teaching tool for aquaculture students, breeds native fish for reintroduction projects, and for supply to zoos and public aquariums for display, as well as breeding selected introduced species for biological control of aquatic weeds throughout New Zealand. This research arm has a long and successful history in the breeding and rearing of a number of fish species, including New Zealand native threatened freshwater‐fish species. The Shortfin eel Anguilla australis, Giant kokopu Galaxias argenteus, Banded kokopu Galaxias fasciatus, Shortjaw kokopu Galaxias postvectis, Koaro Galaxias brevipinnis, Redfin bully Gobiomorphus huttoni, Common bully Gobiomorphus cotidianus, Giant bully Gobiomorphus gobioides, Cran's bully Gobiomorphus basalis, Freshwater shrimp Paratya curvirostris and Freshwater crab Amarinus lacustris have all been bred successfully at MTI. Of these native species, MTI has successfully closed the lifecycle of Giant kokopu, Banded kokopu, Cran's bully, Common bully, Freshwater shrimp and Freshwater crab. This paper focuses on work so far conducted to close the lifecycle of the Shortfin eel and the Giant kokopu.

Effects of flow on lateral interactions of fish and shrimps with off-channel habitats in a large river-floodplain system

Off-channel habitats play a crucial role in the life-cycles of many riverine fish species, but lateral movements of fish into these habitats are poorly understood. We tested how flow dynamics affects the movement of fish and shrimps between the main river channel and different types of off-channel habitats: a riverine lake and a wetland. Our study site was the lower Waikato River, North Island, New Zealand, where there are numerous off-channel habitats. Fish were sampled using directional fyke nets. Shortfin eel (Anguilla australis) migrated mostly into the wetland at night, particularly during high river flows. Common bullies (Gobiomorphus cotidianus) were most abundant during the day and in low-discharge conditions, moving mostly into the riverine lake, whereas freshwater shrimp (Paratya curvirostris) moved mostly into the wetland. High numbers of non-native larval common carp (Cyprinus carpio) moved out of the wetland with retreating flood water. This study emphasises the importance of lateral connectivity and flooding in functioning of this river system where numerous native fish, but also exotic fish, used off-channel habitats. Floodplain management strategies should promote ‘controlled connectivity’ measures that provide access for native species at key times while limiting opportunities for introduced species to utilise their favoured off-channel habitats.

Avoidance behaviour of freshwater fish and shrimp exposed to ammonia and low dissolved oxygen separately and in combination

The responses of common smelt (Retropinna retropinna Richardson), inanga (Galaxias maculatus Jenyns), common bully (Gobiomorphus cotidianus McDowall), and shrimp (Paratya curvirostris Heller) to ammonia and low dissolved oxygen (DO), separately and in combination, were measured in a fluvarium. Only common smelt avoided high or low ammonia (c. 8.5 and 2.0 g m−3 NH3, respectively) and low DO (c. 2 g m−3) alone and in combination. Shrimp avoided high ammonia and low DO+ammonia but not low DO on its own. Inanga and bullies showed no significant negative response to either contaminant; rather, inanga were strongly attracted to low ammonia and bullies to low DO. These results parallel those from toxicity experiments that show common smelt and shrimp are usually among the most sensitive native species to various contaminants. The consistent and appropriate avoidance behaviour shown by common smelt, in particular, suggests this species would be a good indicator organism for assessing the health of lowland waterways.

Responses of seven species of native freshwater fish and a shrimp to low levels of dissolved oxygen

The tolerances of seven New Zealand freshwater fish species and one species of shrimp to low levels of dissolved oxygen were determined in the laboratory by holding fish at dissolved oxygen levels of 1, 3, or 5 mg litre‐1 for 48 h at 15°C. Juvenile rainbow trout (Oncorhynchus mykiss) were also tested for comparison. All of the banded kokopu whitebait (Galaxias fasciatus), juvenile torrentfish (Cheimarrichthys fosteri), adult and juvenile common smelt (Retropinna retropinna), juvenile common bully (Gobiomorphus cotidianus), and trout were dead after 48 h exposure to 1 mg litre‐1. Adult and juvenile inanga (Galaxias maculatus), adult common bully (Gobiomorphus cotidianus), and shrimp (Paratya curvirostris) had mortalities ranging from 27 to 80% at 1 mg litre‐1, whereas all of the elvers (Anguilla spp.) survived. Juvenile rainbow trout were the most sensitive of the species tested, and the only species that had mortalities during exposure to 3 mg litre‐1. No deaths of any fish occurred at 5 mg litre‐1. Time to 50% mortality at 1 mg litre‐1 for common smelt (adult and juvenile) and juvenile common bully were similar to those for juvenile rainbow trout. Most fish moved towards the surface within the first few hours of exposure to 1 mg litre‐1. Rainbow trout was the only species that showed consistent surfacing behaviour at 3 mg litre‐1 and rarely were fish observed to move towards the surface at 5 mg litre‐l. Within the limits of the lifestages and species tested, adequate protection is provided for native fish by adopting the United States Environmental Protection Agency dissolved oxygen criteria for salmonid waters.

Patch- and reach-scale dynamics of a macrophyte-invertebrate system in a New Zealand lowland stream

Abundant growths of macrophytes are a common feature of streams in open lowland areas of New Zealand during summer, but the values of these to aquatic biota are poorly understood. We studied the temporal dynamics of, and associations amongst, elements of a macrophyte-invertebrate system to provide an improved information base for lowland stream management. The biomass of macrophytes increased significantly over the four quarterly sampling occasions from 43.8 g m-2 in June to 370.8 g m-2 in March; biomass was dominated by Egeria densa on all dates, except in December when Potamogeton crispus was dominant. We did not detect strong associations between epiphyton biomass and invertebrate abundance in our study, but this may reflect the fact that we sampled loosely-adhering epiphyton on young, surface-reaching shoots whereas invertebrates were collected from macrophytes growing through the water column. Density of some invertebrate species per gram dry weight of plant material varied by macrophyte type, with the chironomids Tanytarsus vespertinus and Naonella forsythi displaying positive correlations with Egeria and Potamogeton biomass, respectively. The shrimp Paratya curvirostris accounted for 50% of phytophilous invertebrate biomass, with Chironomidae the only other group to comprise more than 9%. Abundance of total phytophilous invertebrates displayed a positive linear relationship with macrophyte biomass in a sample (0.1 m2), and a humped relationship with species richness, such that highest numbers of taxa occurred at macrophyte biomass levels around 400 g dw m-2. Our study suggests that intermediate macrophyte biomass levels are likely to enhance macroinvertebrate biodiversity in sandy-bottomed lowland streams.

Gill-cleaning Mechanisms of Paratya Curvirostris (Caridea: Atyidae) and Comparisons With Seven Species of Japanese Atyid Shrimps

Fresh-water atyid shrimps are an ancient group of carideans that uses passive cleaning mechanisms to protect their gills from fouling. We studied gill cleaning in Paratya curvirostris from New Zealand, and P. compressa, Caridina japonica, C. typus, C. leucosticta, C. serratirostris, Neocaridina denticulata, and Atyopsis spinipes from Japan. Gill cleaning in atyids involves epipod-setobranch complexes, associated with their pereiopods, and multidenticulate setae on the posterior end of the scaphognathite. Multidenticulate scaphognathite setae are particularly well developed in atyids and show a negative correlation with the number of setobranch setae in different species. At one extreme is A. spinipes, lacking setobranch setae but having the largest number of multidenticulate scaphognathite setae, which are relatively longer and have the maximum number of digitate scale setules. At the other extreme are P. curvirostris and P. compressa, with the largest number of setobranch setae but the smallest number of multidenticulate scaphognathite setae, which are relatively shorter and have a smaller number of digitate scale setules. In atyids, there is a compromise between these two gill-cleaning mechanisms. Mapping gill types and gill-cleaning mechanisms on a decapod cladogram suggests that phyllobranchiate gills represent a convergent derived state that evolved independently from trichobranchiate ancestors, in carideans, thalassinids, anomalans, and brachyurans. There are no particular associations between the type of gills and the mechanism used to clean them. Active gill cleaning, using pereiopods, has evolved independently in several lines. If the primitive gill-cleaning mechanism is setiferous epipods, then epipod-setobranch complexes must have been independently derived in carideans and the astacid-thalassinid group. Multidenticulate scaphognathite setae occur with both setiferous epipods and epipod-setobranch complexes. The multidenticulate scaphognathite setae may be the ancestral state for the Pleocyemata, or a synapomorphy of the Caridea, and the Homarida-Astacida-Thalassinida-Brachyura group, having been lost in the Anomala which have active gill cleaning. Atyids are an ancient group of fresh-water shrimps widespread throughout the tropics, with a few species penetrating cooler regions (Ortmann, 1894; Fryer, 1977; Hung et al., 1993). Their diverse habitats include estuaries, ponds, lakes, swift mountain streams, and caves. In all these habitats atyid shrimps are exposed to harmful debris and the attacks of fouling organisms. It is, therefore, necessary for them to clean their body surface and especially the antennae, gills, and embryos. Though cleaning mechanisms are diverse among different species, crustacean decapods generally clean their antenna using the endopodite of the third maxillipeds, the thoracic body and gills using the first, second, and fifth pereiopods or epipodite of the third maxillipeds, and the abdomen and telson using the fifth pereiopods (Bauer, 1975, 1977, 1978, 1979, 1981, 1989; Felgenhauer and Schram, 1978, 1979; Pohle, 1989b; Read et al., 1991). In all decapods, the gills are flushed regularly by the pumping action of the scaphognathite of the second maxilla. Water enters the gill chamber near the posterior thoracopods and exits through the oral region. This respiratory current brings harmful debris and fouling organisms to the gill chamber. The branchiostegite not only protects the gills, but also provides a sheltered habitat for other organisms. A number of gill-cleaning mechanisms have evolved to prevent settlement of fouling organisms (Bauer, 1979; Ritchie and H0eg, 1981; Fleischer et al., 1992). Decapod gills are cleaned by up to four major kinds of appendages: the thoracic epipods with compound setae are mainly used in penaeids, nephropids, palinurids, and brachyurans; the pereiopods in carideans, stenopodids, thalassinids, and anomurans; the epipod-setobranch complex in carideans or setobranchs only in axiids and astacids; and scaphognathite setae (reviewed in Bauer, 1981, 1989). Reversal of the respiratory current also cleans

Responses to pH of nine fishes and one shrimp native to New Zealand freshwaters

The pH values preferred and avoided by adult stages of inanga (Galaxias maculatus), common bully (Gobiomorphus cotidianus), common smelt (Retropinna retropinna), and redfinned bully (G. huttoni), were determined in a gradient tank (pH ranges of 3.2–11.2). Juvenile stages of inanga, common bully, shortjawed kokopu (Galaxias postvectus), koaro (G. brevipinnis), banded kokopu (G. fasciatus), shortfinned (Anguilla australis) and longfinned (A. dieffenbachii) elvers and glass eels, as well as freshwater shrimp (Paratya curvirostris) were also tested. Most species were found to have pH preferences and all except inanga avoided pH values of above c. 9.5. Adult fish showed stronger preferences than juveniles. An avoidance of pH values below 6.5 was apparent in most species except shortfinned elvers, koaro, and banded kokopu. Results indicate that the range of pH encountered in lowland streams are unlikely to have a major impact on the distribution of most New Zealand native freshwater fish.

Upper thermal tolerances of twelve New Zealand stream invertebrate species

The upper thermal tolerances of 12 New Zealand freshwater invertebrate taxa were compared using a laboratory lethality testing protocol. Temperatures that were lethal to 50% of the test organisms (LT50S), following acclimation to 15°C, generally declined over the 4 day period of the tests. LT50 values after 48 and 96 h exposure ranged from 24.5 to > 34°C and 22.6 to 32.6°C, respectively, indicating that temperatures that occur in summer in many NZ streams and rivers may limit the distribution and abundance of some of these invertebrate species. Larval insects included both the most sensitive species (a plecopteran and two Ephemeroptera) and the most tolerant (the larvae of the elmid beetle Hydora sp.) in this study. The two molluscs studied (Potamopyrgus anti- podarum (Prosobranchia: Hydrobiidae) and Sphaerium novaezelandiae (Bivalvia: Sphaeriidae)) showed high thermal tolerance, whilst two crustaceans {Paratya curvirostris (Atyidae) and Paracalliope fluviatilis (Eusiridae)) were moder- ately tolerant. The effect of a higher acclimation temperature (20°C) on thermal tolerance was also investigated for the three most sensitive species. This appeared to increase the thermal tolerance of the two Ephemeroptera {Deleatidium spp. and

Toxicity of ammonia to nine native New Zealand freshwater invertebrate species

The toxic concentration for un-ionized ammonia (NH3) was assessed for nine native New Zealand invertebrate species. The 96-h EC50 values at 15°C and pH 7.6 and pH 8.2 ranged from 0.18 to >0.8 g/m3 NH3. The rank of species sensitivity was: shrimp (Paratya curvirostris) (least) ≈ mayfly (Zephlebia dentata) ≈ stonefly (Zealandobius furcillatus) < Oligochaeta (Lumbriculus variegatus) < fingernail clam (Sphaerium novaezelandiae) < mayfly (Deleatidium spp.) < a snail (Potamopyrgus antipodarum) < caddis (Pycnocentria evecta) < crustacean (Paracalliope fluviatilis) (most). Surprisingly, the more sensitive species were those which would normally be associated with lowland streams (the snail and crustacean) rather than the normally accepted “sensitive” species (mayflies and stoneflies). Temperature had no significant effect on the acute toxicity of un-ionized ammonia with snails tested at 15, 20, and 25°C. The invertebrates were more sensitive than the native fish species tested (inanga, EC50 1.60 g/m3 NH3; Richardson 1991). A final acute value (FAV) calculated for these species was 0.15 g/m3 NH3. This compares with the FAV value of 0.52 g/m3 NH3 derived by the US Environmental Protection Agency (EPA) as the basis for the ammonia criterion for salmonid containing waters. Thus EPA criteria may not provide adequate protection for New Zealand species. These data suggest that chronic studies would be particularly desirable on native New Zealand species to better determine their sensitivity to long term ammonia exposure.

Population biology of the freshwater shrimpParatya curvirostris(Heller, 1862) (Decapoda: Atyidae)

Abstract The life history of the endemic New Zealand freshwater shrimp Paratya curvirostris (Heller, 1862) (Decapoda: Atyidae) in 3 streams in North Canterbury is described. Each female carried on average 2000(±634) eggs and incubation took about 28 days at 14–18°C. Mixohaline planktonic larvae were found in the Ashley Estuary and in small numbers in fresh water. Post‐larvae had a carapace length of 0.5–1.5 mm, and most developed into males which occurred in freshwater streams. At a carapace length of 5.0–6.0 mm males developed into females which could be ovigerous at any time of year and could bear several successive broods. Estimated growth rate was greatest from late winter to early summer with a maximum weekly rate of 1.5 mm carapace length calculated in spring. The behaviour of a female during egg hatching is described in detail.

Acute toxicity of increased pH to the freshwater shrimpParatya curvirostris

The highly alkaline wastes from the ash lagoons at the Huntly thermal power station are a potential hazard to the upstream migration of the shrimp Paratya curvirostris. To test the response of the shrimp to such wastes migrating shrimp were exposed for 48 h in the laboratory to a pH range of 7.47–10.66. The relation between the median period of survival and pH was a typical acute lethal response with an asymptotic value of pH 9.71.

Protandry in the freshwater shrimp,Paratya curvirostris(Heller, 1862) (Decapoda: Atyidae), with a review of the phenomenon and its significance in the Decapoda

Abstract Paratya curvirostris (Heller, 1862) (Decapoda: Atyidae) is the first member of its family found to be protandrous. Reappraisal of published information on Atya bisulcata, Atya serrata and Caridina richtersi indicates that they are also protandrous. The occurrence and biology of protandry in the Decapoda is reviewed. Analysis of available data suggests that protandry has no adaptive value and its frequency in these Crus:tacea is a result of the ease with which decapod reproductive physiology can be modified to produce the phenomenon.