Cheilodactylus Fuscus Research Articles

The Devil in the Deep: Expanding the Known Habitat of a Rare and Protected Fish

Abstract The accepted geographic range of a species is related to both opportunity and effort in sampling that range. In deepwater ecosystems where human access is limited, the geographic ranges of many marine species are likely to be underestimated. A chance recording from baited cameras deployed on deep uncharted reef revealed an eastern blue devil fish (Paraplesiops bleekeri) at a depth of 51 m and more than 2 km further down the continental shelf slope than previously observed. This is the first verifiable observation of eastern blue devil fish, a protected and endemic southeastern Australian temperate reef species, at depths greater than the typically accepted depth range of 30 m. Knowledge on the ecology of this and many other reef species is indeed often limited to shallow coastal reefs, which are easily accessible by divers and researchers. Suitable habitat for many reef species appears to exist on deeper offshore reefs but is likely being overlooked due to the logistics of conducting research on these often uncharted habitats. On the basis of our observation at a depth of 51 m and observations by recreational fishers catching eastern blue devil fishes on deep offshore reefs, we suggest that the current depth range of eastern blue devil fish is being underestimated at 30 m. We also observed several common reef species well outside of their accepted depth range. Notably, immaculate damsel (Mecaenichthys immaculatus), red morwong (Cheilodactylus fuscus), mado (Atypichthys strigatus), white-ear (Parma microlepis) and silver sweep (Scorpis lineolata) were abundant and recorded in a number of locations at up to a depth of at least 55 m. This underestimation of depth potentially represents a large area of deep offshore reefs and micro-habitats out on the continental shelf that could contribute to the resilience of eastern blue devil fish to extinction risk and contribute to the resilience of many reef species to climate change

Size and age are important factors for marine sanctuaries: evidence from a decade of systematic sampling in a subtropical marine park

Abstract Meta‐analyses of disparate studies suggest that size and age of a 'no‐take’ area (marine sanctuary) can influence its ecological response to protection. Few studies, however, have been designed explicitly to test how these factors influence the abundance trajectories of key species within sanctuaries. Diver surveys on reef habitat were conducted within a subtropical marine park in eastern Australia, to test for differences in abundances of targeted fishes between sanctuaries differing in size and age and compared with fished zones. Four management zones were sampled: (i) small sanctuaries established 1991 (<15 ha of reef and <200 m wide); (ii) large sanctuaries established 2002 (>100 ha of reef and > 500 m wide); (iii) zones which allowed recreational fishing but not commercial fish trapping (>200 ha of reef); and (iv) zones which allowed both recreational fishing and commercial fish trapping (>200 ha of reef). Multiple sites in each management zone were sampled for selected taxa eight times during the austral winter from 2002 to 2012. Many of the targeted taxa examined were more abundant in large sanctuary sites within a few years of the establishment of protection compared with the small sanctuary sites and the fished sites. Red morwong Cheilodactylus fuscus increased in large sanctuaries but were more abundant in the older smaller sanctuaries throughout the study. Similar increases were not observed in fished zones. There was considerable variability among years not associated with management type, including a peak in abundance for several species in 2005 and reduced abundance of many taxa following a destructive storm in 2009. This study provides strong empirical evidence that size and age of ‘no take’ areas are important for fish, and indicates that larger sanctuaries can rapidly reach levels of fish abundance similar to smaller older sanctuaries. © 2015 Commonwealth of Australia.

Enhanced numbers of two temperate reef fishes in a small, partial-take marine protected area related to spearfisher exclusion

Reviews of global studies suggest that even small no-take marine protected areas (MPAs) can have localized benefits on harvested organisms of varying mobility. The generality of this conclusion, however, has been questioned due to poor experimental designs of some studies included in reviews, and the relatively small proportion of studies which focused on very small MPAs (⩽1km2). Here we use a correlative approach to test for possible effects of a 0.1km2 partial-take MPA (closed to spearfishing for 12.5years) on the abundance and size of key harvested fishes using an asymmetrical spatial comparison of the MPA vs. three unprotected control areas. Positive impacts were detected, despite our prediction that a small MPA would not provide protection to highly mobile taxa. Densities of legal-sized (⩾200mm SL) Cheilodactylus fuscus (red morwong; relatively sedentary) were 2.8 times greater within the MPA than at the controls and densities of legal-sized Acanthopagrus australis (yellow-fin bream; relatively mobile) were 2.3 times greater on shallow (⩽3.5m) but not deeper (4–12m) areas of reef within the MPA. While benefits of protection were evident, the cost-benefit of implementing similar MPAs should be carefully considered as the partial protection status and small size of the MPA limit both the adequacy of the MPA for protecting a larger range of species, and the magnitude and thus detectability of effects.

Conservation benefits of a network of marine reserves and partially protected areas

Marine biodiversity is becoming increasingly threatened worldwide. To help address this, networks of no take marine reserves are being promoted as a means of conserving biodiversity and managing coastal resources. Many studies have demonstrated the effectiveness of individual marine reserves and metaanalyses have shown that marine reserves provide positive outcomes for marine conservation. Few studies, however, have examined the effects of marine reserves with different levels of protection or examined shallow subtidal areas (1–3m depth). Here, we examine changes within a network of “no take” marine reserves relative to partially protected “take” areas after 5years of operation. We also examine similar open areas outside the boundaries of the marine reserve network. We show that some targeted species including red morwong (Cheilodactylus fuscus) and abalone (Haliotis rubra) were more abundant in marine reserves than elsewhere. Fish assemblages inside the marine reserve network differed from those outside the boundaries of the reserve network. This result was driven by habitat differences; abundant, schooling species of fish were more commonly encountered outside the marine reserve where urchin barrens dominated. The combination of large spatio-temporal variation in reef assemblages and variable effects of early reserve protection in shallow subtidal habitats made it challenging to detect other changes among zones. Careful consideration of variation in the design and analysis of shallow subtidal reef monitoring is necessary to ensure such programs can best inform adaptive management processes.

A review of the biology and ecology of key fishes targeted by coastal fisheries in south-east Australia: identifying critical knowledge gaps required to improve spatial management

Knowledge of the population biology, life-history ecology and scales of pre and post-settlement movement of marine species are needed to inform effective conservation management strategies, particularly when spatial information is required for management purposes such as zoning in Marine Protected Areas. This review provides the most current summary from primary and grey literature on the biology and ecology of several coastal fishes of economic and ecological significance in south-east Australia; identifies key knowledge gaps which may impede the development of effective spatial management; and recommends future research directions and methods. Reviewed species are luderick (Girella tricuspidata), eastern rock blackfish (Girella elevata), yellowfin bream (Acanthopagrus australis), tarwhine (Rhabdosargus sarba), snapper (Pagrus auratus), red morwong (Cheilodactylus fuscus) and eastern blue grouper (Achoerodus viridis). The species have a diverse range of life-histories and population traits, and selected parameters were well studied in several species, such as growth (blue groper, luderick, yellowfin bream, tarwhine, snapper), post-settlement movement (red morwong), and larval ecology (yellowfin bream). However, empirical data on levels of pre- and post-settlement connectivity and real-time movements are not available for most species, and this represents a significant gap for improved spatial management. A multidisciplinary approach incorporating a range of methods including acoustic tracking and telemetry, otolith chemistry, intergenerational markers, and biophysical modelling will provide a more comprehensive understanding of life history parameters, movement and connectivity at scales relevant to MPA planning and monitoring.

Life cycle characteristics of the Blue Morwong Nemadactylus valenciennesi, compared with those of other species of Cheilodactylidae

The demonstration by this study that the life cycle characteristics of the reef fish Nemadactylus valenciennesi differed markedly from those of other cheilodactylids led us to compare these differences and hypothesise on their evolutionary implications. The distribution, length and age compositions, growth and the length and age at maturity of N. valenciennesi in south-western Australian waters have been determined. The maximum age (21 years) of N. valenciennesi (maximum total length = 984 mm) is far less than those of the much smaller Cheilodactylus fuscus, Nemadactylus macropterus (both ~40 years) and Cheilodactylus spectabilis (97 years). Yet N. valenciennesi, N. macropterus and C. spectabilis mature at a similar young age (3–7 years). While, on the basis of data for other species, all three species mature at lengths consistent with their asymptotic lengths, the last two species mature at a far earlier age than would be predicted from their long life spans. The early attainment of maturity by N. macropterus and C. spectabilis may reflect a response to high juvenile mortality or constrained adult growth, whereas their long life spans could reflect a response to variable recruitment in the past or compensation for limited annual reproductive output due to very constrained adult growth.

Population structure of aggregations, and response to spear fishing, of a large temperate reef fish Cheilodactylus fuscus

Strip transect surveys of the large temperate rocky reef fish Cheilodactylus fuscus revealed size- and sex-structured populations across seasons and 3 conditions of wave exposure, from an estuary to the open coast. Large, mostly male, fish (> 30 cm fork length) predominated on the open coast and in deeper water (>10 m), while smaller fish predominated in the more protected estu- arine areas and in the subtidal regions ( 70% of the adults by intense spear fishing. Experimental sites were recolonised by > 20 cm males and females, and rarely by juveniles. There was no significant differ- ence between the pre- and post-removal estimates of home range of tagged fish at removal sites or in controls.

Age and growth of Cheilodactylus fuscus, a temperate rocky reef fish

To provide information on age and growth of red morwong (Cheilodactylus fuscus Castelnau), populations were sampled from eight locations over a 2.5‐year period with the majority of fish sampled from six sites within Sydney Harbour, New South Wales, Australia. Transverse thin sections of otoliths taken from a total of 347 fish were used to determine age. Age estimates were validated using oxytetracycline (OTC) marking and marginal increment techniques. Validated otoliths indicated that this species forms one annulus per year over an extended period from April to October. Age varied from “0” (<1 year old) to 40 years. A comparison of otolith weight and otolith radius determined that otolith weight was the more accurate physical determinant of age. Von Bertalanffy growth estimates based on length (t0 = ‐1.8, k = 0.32, L = 37.64) indicated that growth is most rapid over the first 6 years, with fish being close to their asymptotic length by 7 years. There was no significant difference in length between sexes although females were significantly older than males. Comparisons of growth curves did not indicate any significant differences in the rate of growth between sexes.

Home range, activity and distribution patterns of a temperate rocky-reef fish, Cheilodactylus fuscus

Red morwong (Cheilodactylus fuscus; Cheilodactylidae: Perciformes), are large temperate rocky reef fish that are patchily distributed in local aggregations of 3 to >100 fish. The home ranges and aggregating behaviour of red morwong were investigated using external tags (n = 114, over 35 mo) and ultrasonic transmitters (n = 9 over 20 d) at coastal and estuarine sites in south-east Australia. Adult red morwong had a mean home range during the day of 1865 m2 (SE = 268). Night movement, determined by ultrasonic telemetry, indicated a significantly greater mean home range of 3639 m2 (SE = 416). Home range did not differ significantly with size or sex. Fish movements were greatest and aggregation sizes varied most during the non-reproductive mid-summer period. Tagged fish (N = 20) displaced 200 to 900 m returned in 1 to 3 d to the point of capture, often traversing open sand habitat and other aggregations. During the day, fish were commonly found on bouldered habitat. During the night, these site-specific aggregations fragmented as fish dispersed over a variety of substrata, with crepuscular peaks in activity. Therefore, estimates of habitat-specificity and feeding patterns collected only by day may give misleading results.

Health of red morwong, Cheilodactylus fuscus, and rock cale, Crinodus lophodon, from Sydney cliff-face sewage outfalls

Health of red morwong, Cheilodactylus fuscus and rock cale, Crinodus lophodon was assessed using histology to determine effects of the Sydney cliff outfalls on these two species. Ten individuals of each species were sampled from three outfall sites and three control sites. Benign epitheliocystis, presence of metazoan parasites, epithelial lifting, telangiectasis, haemorrhage and inflammation were found in the gills of some individuals. Hemosiderin was present in melanomacrophage aggregates in liver and spleen of some fish and also in kidneys of a few fish collected in Malabar outfall site. Hyaline droplets were present in tubular epithelium in kidney of some fish, particularly in the individuals collected from Malabar. Although for some changes there was a trend of greater prevalence at the outfall sites, there was no statistically significant difference between the fish from outfall sites and control sites. Most changes were species specific and the differences were statistically significant. This suggests problems with extrapolating results from one species to others. Greater replication, smaller range of size, chemical analysis of tissue residues as well as better knowledge of the fate of sewage and oceanographic processes would improve interpretation of any future surveys. A multidisciplinary approach would be most beneficial for pollution studies.

Organochlorine compound and trace metal contaminants in fish near Sydney's ocean outfalls

Sydney's inshore sewage outfalls were significant contributors to organochlorine contamination of inshore sedentary fish such as red morwong. Diversion of the sewage to deepwater outfalls has resulted in marked declines in the concentrations of these compounds in inshore red morwong. Apart from lead, however, similar trends did not occur for concentrations of trace metals. A wide variety of trace metals and organochlorine compounds were found in the flesh and/or livers of a variety of fish species caught at sites associated with the present deepwater ocean outfalls off Sydney. Fish caught at locations remote from Sydney also contained a wide variety of trace metals although organochlorine compounds were usually at lower levels. The mean contaminant levels in all species of offshore fish were generally found to be low when compared to the Australian National Food Authority's Maximum Residue Limit (NFA MRL). No fish analysed was found to have levels of an organochlorine compound above the MRL and no fish was found to have levels of zinc or lead above the MRL. When detected, fish with levels of a trace metal above the MRL appeared to be distributed throughout New South Wales, independent of the deepwater ocean outfalls off Sydney. There is no evidence as yet that the commissioning of the deepwater outfalls has led to an increase in levels of contaminants in the fish examined to the extent that they are of concern relative to the NFA MRLs.

Sexual dimorphism in the red morwong, Cheilodactylus fuscus

The red morwong, Cheilodactylus fuscus Castelnau (Pisces : Cheilodactylidae), is a conspicuous fish on the rocky reefs of the eastern Australian coast. Visual determination of the sex of individuals in the field is necessary to remove sex bias in home-range and associated bioaccumulation studies. A sample of 61 fish (30-50 cm fork length) was collected from spear-fishing competitions in the Sydney area, and from each fish 16 morphometric measurements were taken. A multivariate analysis revealed that, in comparison with females, males are generally larger, with a significantly larger orbit-tubercle - or horn - situated in front of each eye, a smaller eye diameter and a smaller head length. A discriminant function analysis derived from these four features correctly identified 87% of an independent sample of 40 fish. Visual appraisal of fish on the basis of the proportional length of the horns misidentified &lt;10 % of fish &gt;30 cm and &lt;30% of fish 20-30 cm fork length. The orbit-tubercle in males is between 2% and 4% of the fork length and is composed of bone. According to this simplified visual technique, red morwong aggregations in the Sydney region have consistently biased sex ratios.

Effect of three primary treatment sewage outfalls on metal concentrations in the fish Cheilodactylus fuscus collected along the coast of Sydney, Australia

Samples of muscle tissue from red morwong Cheilodactylus fuscus (Pisces: Cheilodactylidae) collected at 24 sites along the coast near Sydney Australia were analysed for total concentrations of mercury, arsenic, selenium, zinc, cadmium, lead, nickel and copper. The sites were equally spaced around each of the three major ocean disposal sewage treatment plants (STP) in Sydney located at North Head, Bondi and Malabar. The mean concentrations of mercury, arsenic and zinc were highest in fish caught off Sydney Harbour and Malabar STP. The proportion of fish in which cadmium was detected was also highest off Sydney Harbour and south of Malabar STP. Average selenium concentrations decreased from north to south with peak concentrations at each STP. Many individual values of copper, lead, and nickel were near or below the detection limits and no notable trends were observed for these metals. Mercury was the only metal whose overall mean concentration exceeded the National Health and Medical Research Council (NHMRC) Maximum Residue Limit (MRL).

Seven new coccidian species from marine fishes in Australia

One hundred and thirty fish of 15 species from the coast of northern New South Wales, Australia, were examined for coccidia. Seven new species, Eimeria cheilodactyli n. sp. and E. dykovae n. sp. from Cheilodactylus fuscus; E. pleurostici n. sp. from Sphaeroides pleurosticus; E. sillaginis n. sp., E. ciliatae n. sp. and Goussia arrawarra n. sp. from Sillago ciliata; G. microcanthi n. sp. from Microcanthus strigatus as parasites of the intestine; and a Goussia sp. from the liver of Rhabdosargus sarba are described.