Reef Ramblings

While starting to research unsuitable fishes for SAIA, I remembered this article from a couple of years back. Hopefully this should explain some of the rationale behind restricting the availability of certain species of fish. Personally I would not want to see the trade in these species banned, rather that availability should be restricted to:  those with the capacity to provide suitable accommodation - in the case of large species, advanced aquarists  - in the cases where it’s a matter of nutritional limitations.

Criteria for Unsuitability.

SAIA’s criteria for unsuitability include: size (organisms growing too big for the average hobbyist tank), feeding (specialist feeders), and sensitivity to transport conditions. We believe that as part of our goal of an ethical and sustainable marine aquarium trade that we can reduce the demand for unsuitable species by making information available to both the trade and the hobby. Below are a few further comments on some of the criteria for unsuitability.

Generation replacement time.

Many fishes have a slow generation replacement time; meaning collection for the aquarium trade can affect the sustainability of the breeding population.

Rarity in the wild.

Some very desirable species are comparatively rare in the wild.

Limited natural range.

A good example of course being the Banggai, a limited range implies a small population that can be easily over-exploited by the aquarium trade.

Method of capture.

Owing to their habitat there are fish species, which are difficult to capture, fishes such as dwarf angelfishes and mandarins come to mind. Cyanide is still in use, along with a number of other chemical agents that are used to knock out fishes to make collection easier.

Nutritional requirements.

If you can’t feed it, you can’t keep it!

Just because some retailer tells you, “No problem, it’ll eat anything” it doesn’t mean that they’re correct. Research fishes’ nutritional requirements, if you cannot accommodate a specialist feeder do not buy it thinking it’ll acclimate to aquarium food in time, it won’t, it’ll starve to death!

Size.

This is of particular importance in view of the public aquarium Big Fish Campaign, launched in 2006, which aims to educate aquarists about the potential sizes of fishes in the trade and point out that public aquaria cannot be relied upon to take care of poorly thought out purchases, when they outgrow home aquaria.

Remember, when you buy a fish it shouldn’t just be something to keep until it outgrows your system, you should be making a commitment to keep that fish for the length of its natural life, something that in many cases should be measured in decades not months!

On the subject of size, there is also the question of what size fish should be collected for the trade, this can affect the sustainability of the breeding population of a species. Size can also have an influence on how well a particular species survives the process of collection and transportation.

10 Marine Fishes You Shouldn’t Even Think About Buying.

Elasmobranches.

Elasmobranches, sharks and rays, should remain the provenance of public aquaria. The only exception to this rule is if you can provide facilities similar to those of a public aquarium, both in scale and in technology.

I’d particularly like to draw your attention here to the Blue-spotted stingray, Taeniura lymma. This is an animal that is being put into danger by collection for the marine aquarium industry and features in the IUCN Red List of Threatened Species. It’s of particular concern as it has a poor record in captivity with a significant number of those brought in for public aquarium display failing to survive the acclimation process. If public aquaria, with their knowledge and facilities, find these difficult animals what chance do hobbyists have of keeping them alive?

Carangidae (Jacks).

Few, if any, fishes from this family are suitable for the home aquarium. The Golden Trevally, Gnathanodon speciosus, is my poster fish for animals that should not be imported unless ordered specifically for a public aquarium display. It is completely irresponsible for these fishes to be imported and held as a matter of course, it’s inevitable they’ll end up in the wrong hands (i.e. outside the public aquarium industry) when picked by people ignorant of the size of these fishes. At 6 -7 cms it’s a cute colourful fish, full grown at 120 cms, it becomes something that smaller public aquaria may have problems housing.

Wild Caught Clownfishes.

You might find this one a bit of a surprise but it makes complete sense. Every Clownfish taken from the wild means the potential demise of its host anemone, a potential that becomes even greater when it’s a pair that’s been collected.

All Clownfishes can be bred in captivity with differing degrees of difficulty, and contrary to uninformed opinion the colours of captive bred fishes can be just as vibrant as those of wild ones.

Ribbon Eels.

Rhinomuraena quaesita, with its nasal extension is a very striking fish. It’s unique amongst the Muraenids in displaying sexual dichromatism, males and female being differently coloured. It’s a protandrous hermaphrodite starting off life black, as it changes to male it takes on the very attractive blue colouration associated with this fish, finally becoming female at around 85 cms when the colour changes to yellow or yellowish green/blue.  These fish are difficult to feed, rarely surviving for more than a year in an aquarium; consequently, the female colouration is seldom seen in captivity.

Wild Caught Banggai Cardinalfishes.

Perhaps another surprise, but this is a classic example of an animal that is easily bred in captivity yet endangered in the wild by the aquarium industry. This fish inhabits a limited range; it produces small broods, and is limited in the number of broods it can produce over the course of the year.

Obligate Corallivores.

Unless you’re prepared to devote a separate aquarium to coral cultivation, one that can keep up with the demands of the fishes being kept, you shouldn’t buy any obligate corallivores. These are fishes that are obliged to eat coral polyps as a mainstay of their diet. Typified by Butterflyfishes plus the gorgeous Blue-spotted filefish Oxymonacanthus longirostris.

Mandarinfishes.

This one is difficult for me as, along with many other aquarists, this is one of the fishes that attracted me to the hobby in the first place. There are two concerns about Mandarins the first is a question of nutrition but if carefully considered there’s no reason why these fishes can’t survive their natural lifespan in an aquarium. The second is harder to defend and is concerned with the manner in which these fishes are collected. There is a tendency for the largest males to be targeted for collection, which has been proved to have a deleterious affect on the local population.

Cleaner Wrasses.

Labroides dimidiatus, the familiar blue cleaner wrasse, is a perpetual concern. They’re commonly seen for sale at a moderate price yet the majority of them are doomed to death by malnutrition. They’re obligate cleaners that feed on external parasites, mucus, and fish scales. To survive long-term they need to be kept with a large community of fishes. There is no excuse for an aquarist with an average sized reef to go out and purchase one of these fishes as, even though these fish will be seen to feed, they are unable to properly assimilate aquarium foods and will die prematurely.

Importantly, they cannot be considered a cure for diseases such as white spot - one of the main reasons hobbyists purchase this fish.

Cowfishes & Boxfishes.

Ostracion cubicus, Yellow or Cube Boxfish, Lactoria cornuta, Longhorn Cowfish, etc. are often seen as cute little “croutons” about 2 cms cubed, hovering in dealers’ sales tank, these are not fish to be taken on lightly. With an adult size of around half a metre, and the potential to wipe out a complete system with the toxic slime that they exude when stressed, they certainly represent a species unsuitable for the average marine aquarist.

SAIA

As I said at the beginning of this article, I’m currently compiling a list of unsuitable fishes for SAIA, if you would like to suggest any species that you believe should be included in this list please contact me at: tim@midlandreefs.co.uk

Tim Hayes

Midland Reefs

©2008 ©2010

Reef Scientific Calanoid Copepods

The highest quality frozen natural marine zooplankton available anywhere!

High Nutritional Value!

High in protein, in omega3, Phospholipids, DHA & EPA, and Astaxanthin.

Although other companies market the calanoid copepod, Calanus finmarchicus, the nutritional quality of these is poor owing to the presence of autolytic enzymes that degrade fatty acids and proteins after freezing. With Reef Scientific Calanoid Copepods, these autolytic enzymes have been deactivated, consequently extending the storage time of the food from as little as one month to in excess of a year with no loss of nutritional value!

Non-polluting!

100% clean. Needs no pre-rinsing before use. The product is pasteurized for bio-security and sealed, using natural components from crustaceans, minimizing nutrient leakage in the reef aquarium. Can be thawed and kept in the refrigerator for up to 14 days.

Suitable for all saltwater and freshwater fish, corals, and crustaceans.

Originally developed in Norway as an initial feed for larval and juvenile stages of marine aquaculture species, it has since proven valuable for ornamental aquarium species. Trials have shown them to be particularly useful in larvaculture since almost all larvae of fish or crustaceans have high nutritional demands during their early stages of development,

This range of marine zooplankton is produced in land-locked bays in Northern Norway and, characteristically of high latitude calanoid copepods, are rich in phospholipids, essential fatty acids and proteins along with the caratanoid Astaxanthin. The fatty acid, DHA, is only produced in marine algae and is accumulated in zooplankton as they graze in a process of natural enrichment.

Although it’s not widely known, there is a problem associated with the preservation of zooplankton through freezing without the degradation of fatty acids and proteins. Zooplankton contains large amounts of autolytic enzymes that continue to degrade their fatty acids and proteins post mortem. These enzymes remain active when zooplankton is frozen; consequently, the maximum storage life is one month before valuable Phospholipids in the zooplankton become degraded.

Our Norwegian partners have succeeded in deactivating the autolytic enzymes present in the zooplankton; consequently, the storage time of the food has been extended to more than one year without loss of nutrients.

Furthermore, they have developed a method of coating the zooplankton with an ultra thin membrane derived from natural components of crustaceans that prohibits nutrient leakage from the food particles. This results in a frozen food of very high nutritional quality that will not pollute the aquarium by leaching nutrients into the water.

Size Range.

The food ranges in particle size from 2mm down to 0.1 mm. Currently only the 2mm size is generally available, although if you are a breeder please talk to us about the smaller size fractions. With the exception of the 2 mm zooplankton, C. finmarchicus, a number of different species are present in each sizing, providing a rich variety of different nutritional profiles. The smaller size fractions of our feed can be used to substitute the use of live feed such as rotifers and artemia. These are available, in small volumes, in the following size fractions 65-80, 80-150, and 150-200 µm, covering the size range of rotifers.

Although other companies market calanoid copepods, specifically Calanus finmarchicus, the nutritional quality of these is poor, as the autolytic enzymes have not been deactivated.

Aquarium

Aquarium shops in Norway trialing the product have been unambiguously positive. After 2-4 weeks feeding, all fish species responded with stronger and more intense coloration. Wild caught fish, fed with this food when first received, had a higher survival rate.

Clownfishes

The smaller-size food particles have a documented positive effect on fish and crustacean larvae.

In co-feeding experiments, clownfish have shown 100% higher growth compared to a diet solely with enriched rotifers and artemia. Survival has increased by 50%.

Norwegian ornamental fish breeder, Thomas Engels, has done extensive testing of the product and has substituted the artemia feeding period of clownfishes by 2-3 weeks using this product, finding it be the best food he’s ever used.

Dr. Ike Olivotto at the university of Ancona, Italy, is shortly to publish a paper showing this food to be superior to live feeds such as rotifers and artemia. His research involved comparing two groups of clownfish larvae, one group fed a standard rotifer/Artemia nauplii, diet, the other fed a combination of rotifers/copepod nauplii and Artemia nauplii/copepodites-copepods.

Analysing gene expression in clownfishes, growth promoting factors increased by 2.5 times, whilst growth-inhibiting factors (myostatin) decreased by 5 times. His research showed 100% higher weight along with 30% length increase in clownfishes 10 days post hatching, compared to fish given a diet consisting of enriched rotifers and Artemia. 15 days post hatching, larvae fed with the copepod enhanced diet had a 62% survival rate compared to larvae fed a conventional rotifer/Artemia nauplii diet with a 41% survival rate.

Aquaculture

A Norwegian lobster hatchery, Norsk Hummer AS, trialing the 500-700µm frozen food, found that the survival rate of lobster larvae during the three weeks prior to settlement, increased to approximately 15% from less than 1%! This increased survival rate was evident even when the lobster eggs were of poor quality.

In the UK, after an initial trial, the National Lobster Hatchery are now using the 2.0mm Calanus finmarchicus as part of their raising protocol.

The food is currently being trialed on newly hatched cod larvae with further testing on growth and survival planned for other species such as halibut, turbot and cleaner fish.

Midland Reefs, Unit 10 Mount Rd. Trading Estate,

Burntwood. Staffordshire, WS7 0AJ. UK.

Tel: +44 (0) 1543 685599

Zooplankton Technical Data.

Table 1. Size and Species

Size	Species
2 mm	Calanus finmarchicus	Food for adult planktivores and other fishes.
700-1000 µm
5-700 µm	Calanoid copepods Temora longicornis, Acartia clausi and Centropages hamatus. Additionally includes smaller quantities of the calanoid copepods Pseudocalanus spp., Paracalanus spp., Microcalanus spp. and early copepodites of C. finmarchicus	Food for smaller planktivores and juveniles
4-500 µm	T. longicornis, along with early copepodites of A. clausi, C. hamatus, Pseudocalanus spp., Paracalanus spp. Adult Microcalanus spp, and the cyclopoid copepod Oithona similis
3-400 µm	T. longicornis copepod nauplii Early copepodites of all calanoid copepods mentioned above,	Equivalent in size to 2 day old enriched artemia.
2-300 µm	Very young copepodit stages and nauplii of various copepod species. Additionally includes 2-5% bivalvia and gastropod larvae and 2-3% single celled Phytoplankton as Coscinodiscus spp. and Ceratium spp.	Equivalent in size to newly hatched artemia.
150-200 µm		Equivalent in size to rotifers
80-150 µm		Equivalent in size to rotifers
65-80 µm		Equivalent in size to rotifers

Table 2.

Fatty acid profile (mg/g dry weight and % of total fatty acids) of the 2 mm size fraction of copepods.

Fatty acid profile may vary depending on season, locality, and plankton species grazed.

Tim Hayes

Midland Reefs

©2010

In my article, “2010, the International Year of Biodiversity - Clownfishes.” under the section entitled, “Can clownfish adapt to climate change?” there was a mention that one species of clownfish had recently been shown to use soft corals as an alternative habitat, something previously only seen in captivity. This is referenced to Arvedlund, M., and Takemura, A. (2005) Long-term observation in situ of the anemonefish Amphiprion clarkii (Bennett) in association with a soft coral. Coral Reefs 24, 698-698.

Having managed to track this paper down I can now expand on the reference.

Between May 2003 to December 2004, during the course of 37 daytime snorkeling surveys between the hours of 11.00 and 18.00, an adult Amphiprion clarkii was observed at a depth of 1 m, living in the same soft coral, a Lobophytum species of around 90 cms in diameter.

This took place in the Ryukyus Archipelago in southern Japan, at the southernmost local reef of Sesoko Island. This area was seriously affected by the global bleaching event of 1998; in the aftermath of this event several species of host anemones disappeared while the surviving anemone species declined. At the time of the paper, 2005, the anemone population had yet to recover.

Although anemonefishes are known to adopt a wide range of soft corals in captivity, this form of behaviour is almost unknown in the wild.

All 28 known species of anemonefishes have an obligate symbiotic relationship with at least one of ten species of anemones belonging to the families: Actiniidae, Stichodactylidae and Thalassianthidae. There tend to be species specific associations which range from Premnas biaculeatus, Maroon Clownfish, associating with a single species of anemone, Entacmea quadricolor, Bubble-tipped Anemone, to Amphiprion clarkii which has been found in association with all ten species of known host anemone.

From personal observation, the main author of the paper, reports that A. clarkii will often take shelter away from its host anemone when pursued by a potential predator whereas most other anemonefishes, take refuge in their host anemone.  The paper ends by speculating whether the ability of A. clarkii to associate with a wide range of anemones and, as has now been observed, with corals might go some way towards explaining why it’s the most widely distributed species of clownfish.

Other than the fact that Lobophytum species soft corals are amongst the most toxic of corals, something that might deter predation by fishes and aid the coral in competition against other corals, this species appears to offer little in the way of protection for a clownfish. This leads me to further speculate whether A. clarkii is evolving away from its obligate association with host anemones or to question if this is just one fish that has been unfortunate enough to lose its host yet been lucky enough to survive for so long in the absence of an anemone.

More reports of clownfishes, particularly A. clarkii, are required before we can come to any conclusions.

Tim Hayes

Midland Reefs

©2010

The United Nations has declared 2010 to be the International Year of Biodiversity. It is a celebration of life on earth and of the value of biodiversity to our lives. The world is invited to take action in 2010 to safeguard the variety of life on earth: biodiversity

As part of the International Year of Biodiversity (IYOB) the IUCN has published a report presenting 10 new climate change flagship species to demonstrate that it’s not just the Polar Bear that’s in trouble.

These 10 species are as follows:

Staghorn corals

Ringed Seal

Leatherback Turtle

Emperor Penguins

Quiver Trees

Clownfish

Arctic Foxes

Salmon

Koalas

Beluga Whales

One thing that is immediately obvious from the list is that 7 of the species are marine animals. The second thing to strike me about this list is that 2 common aquarium animals are included, most worrying of all is the inclusion of the poster animal of the marine aquarium hobby, the clownfish

In this first of two articles I’m going to look at clownfish, the second article will be concerned with Staghorn corals.

Clownfish and Climate Change

Clownfish, or Anemonefish, belong to the Family Pomacentridae, with their vivid orange and white colouration are one of the most familiar species of tropical marine fishes. This familiarity was boosted by the film ‘Finding Nemo’, which featured the Common Clownfish, Amphiprion ocellaris, a mainstay of the marine aquarium hobby.

Clownfish are found in tropical and subtropical areas of the Pacific and Indian Oceans where they are restricted to shallow waters owing to their mutualistic relationship with a small number of specific anemone species. A host anemone can support a colony of several clownfish consisting of one female, one functional male, and a number of subordinate fishes, all non-functional males.

When the female dies the male turns into a female whilst the largest subordinate fish becomes male. Clownfish lay their eggs close by their host anemone, guarding them until they hatch. On hatching the larvae disperse into the water column where they remain for around 8 to 12 days before settling out as juveniles and seeking a host anemone of their own. As larvae develop, chemical signals allow them to detect suitable host anemone.

Research has shown that the larvae that survive to settle out as juveniles tend to return to the reef where they originated so the majority of the survivors do not disperse very far from their parents’ anemone.

There are 28 species of clownfish described to science; all behave in a similar manner, exhibiting reliance on their obligate association with host anemones for survival.

Captive breeding.

Clownfish have been bred in captivity since the early eighties so we have a lot of information about how different environmental conditions such as temperature and pH affect this species. Although it’s interesting to note that the recent studies from the reef, revealing that reduction in ocean pH levels have an affect on clownfish’s ability to detect the chemical signals necessary for locating an anemone host, answer the question of why captive bred clowns are often slow to adopt an anemone in a reef aquarium.

Why are Clownfish vulnerable to the effects of climate change?

Habitat loss: Coral reefs are in decline owing to increased levels of CO2 in the atmosphere. The current level stands at 387 ppm CO2, higher than 350 ppm that many leading scientists say is the safe upper limit for carbon dioxide in our atmosphere, and the level we need to get back to as early as possible to avoid runaway climate change. If CO2 levels reach 450 ppm, predicted to occur by 2030-2040 at the current rates of increase, reefs will be in terminal decline worldwide from mass bleaching, ocean acidification, and other environmental impacts. Clownfish are dependent on anemones for their survival, which most frequently occur on coral reefs.

A couple of examples: the global coral bleaching event of 1998, led to the complete disappearance of several sea-anemone species used by clownfish in the corals reefs around Sesoko Island, Japan, causing local population declines; and take a look at: Reef Ramblings June/July 2008 to see an earlier article about reduction in clownfish numbers on the Great Barrier Reef.

Disruption of navigation: Decrease in ocean pH levels have been shown to affect a clownfish’s ability to detect the chemical signals that allow them to locate a host anemone. This is known to be a particular problem for juveniles as, if they’re unable to locate a host, they’re at greater risk of predation. Juveniles unable to locate a new anemone face the chance of returning to their parental anemone, increasing the likelihood of inbreeding.

Larval development: As ocean temperatures increase we’d expect to see faster development of larval and juvenile clownfishes. This may bring a reduction in dispersal distance with the result of settlement closer to the parental anemone increasing local competition for recruitment to neighboring host anemones. Again increasing the possibility of inbreeding.

Reproductive behavior: Clownfish, along with many other fish species, only reproduce within a narrow temperature range. This presents the possibility that as temperatures increase that there may be a reduction in breeding activity. A secondary problem that we’re familiar with from captive breeding is that high temperatures can have a deleterious affect on egg development.

It’s also worth noting that in the IUCN report, under the heading of “Other threats”, that the marine aquarium industry is singled out for mention, although it does go on to add that the greatest threat is down to human activities, presumably the usual

Can clownfish adapt to climate change?

Currently this is unknown, most species can usually adapt to changes in environmental conditions as long as these change occur slowly over time. As ocean temperatures continue to increase, clownfish and their associated host anemones may be able to shift their ranges southwards to cooler water. However, neither clownfishes, nor their anemones, are particularly mobile so it’s likely that successful relocation to new, more suitable habitats will be limited.

The concern about more rapid larval development, with its resultant limitation on dispersal, raises the question of inbreeding, the consequences of which are unknown.

A further possibility, but one that seems to me unlikely, is whether clownfishes could adapt to seasonal breeding pattern taking advantage of the cooler seasons.

Interestingly, the IUCN report states the one species of clownfish has recently been shown to use soft corals as an alternative habitat, something previously only seen in captivity. This is referenced to Arvedlund, M., and Takemura, A. (2005) Long-term observation in situ of the anemonefish Amphiprion clarkii (Bennett) in association
with a soft coral. Coral Reefs 24, 698-698.

It’s not known if other species of clownfish could adopt other host species, nor whether such associations would have the same value as the present association with anemones.

What can we do?

Whilst climate change does not mean extinction, some species will be able to adapt whilst others will perish. The question is which species will survive and which will perish? Worsening climate change effects are inevitable, even if all CO2 emissions ceased today, because of the lag-effects of the greenhouse gasses already emitted.

It’s up to all of us, along with our governments, to commit to targets to reduce emissions at the earliest opportunity if, we want to slow the pace of climate change and give clownfishes and other species a chance to survive.

If you are a reefkeeper, try to raise awareness of the destructive affects of climate change to the marine environment by using the familiar clownfish as an example of what may be lost.

You can download the IUCN report here: Species and Climate Change

Tim Hayes

Midland Reefs

©2010