Aquarium fish sourcing: use vulnerability scores carefully

A ranking should lead to better questions

Availability and suitability for an exhibit are only part of a marine fish acquisition decision. A public aquarium also needs to consider whether source populations can sustain collection. For many species in the aquarium trade, reliable information on catches, collection sites and population status remains limited.

Baillargeon and colleagues present a productivity–susceptibility analysis, or PSA, for 306 marine aquarium fish species in 2026. It combines biological traits with factors related to exposure to collection pressure. The resulting ranking identifies priorities for further investigation. It does not certify that a fish offered by a supplier comes from a sustainable operation.

Consider population renewal alongside collection pressure

Productivity represents a species’ biological capacity to replace individuals. The assessment draws on maximum size, trophic level, reproductive strategy, fecundity and pelagic larval duration. Producing many eggs is not equivalent to achieving high recruitment in every wild population, so these traits must be interpreted together.

Susceptibility concerns exposure to fishing pressure. The framework includes geographic range, habitat specificity, depth, aquarium care difficulty, trade volume and the life stages collected. Two species with broadly similar reproductive biology can therefore receive different priorities because their exposure differs.

A species with low productivity may warrant attention even when its recorded trade volume appears modest. Conversely, a large number of imports does not independently demonstrate that a population is overfished. The benefit of the framework is that it makes the reasons for concern more explicit than a single trade-volume comparison would.

Understand what the underlying records describe

An important component of the trade information comes from United States import invoices from 2011. Those records support a structured comparison, but they do not measure every fish collected worldwide or describe every supplier’s current practices. Dividing volumes into categories reduces dependence on exact counts without removing the limits of the dataset.

Biological inputs come from scientific publications, databases and aquarium grey literature. When species-specific information is missing, related-species estimates or expert input may be used. This makes assessment possible for poorly studied species, while retaining uncertainty about how well a substitute value represents the species itself.

The analysis groups species into three relative vulnerability clusters. Their boundaries depend on the assessed dataset and modelling choices. A cluster is not a measured probability of extinction, an estimate of remaining stock abundance or permission to collect animals from a particular reef.

Apply the framework to acquisition planning

The authors highlight slowly renewing groups, including some elasmobranchs and eels. They also call for assessments better suited to elasmobranchs because the framework is primarily tailored to reef fishes. A public aquarium should therefore avoid applying the same interpretation indiscriminately across its collection.

A useful first step is to identify proposed acquisitions that need stronger supporting information. For each species, ask where the animals originated, whether they are wild-caught or captive-bred, which life stage is supplied and what traceability is available. A missing answer should remain an open question rather than being replaced by a global average.

Captive breeding may offer an alternative, but the provenance of the actual shipment still needs checking. Demonstrating that a species can reproduce in captivity does not establish that captive-bred animals are routinely available or that the fish being purchased were produced that way. Supplier statements must connect to the animals acquired.

This approach also helps explain a decision to defer an acquisition. The team can identify which information would change its assessment, rather than relying on a vague judgement that a species is either acceptable or unacceptable. The score is a starting point for that discussion, not its final authority.

Keep conservation, legality and husbandry distinct

Conservation status and vulnerability to a particular trade address different questions. A global species assessment may consider multiple threats, whereas this PSA focuses on collection for the marine aquarium trade. Their rankings can differ without one simply replacing the other.

Legal requirements must be checked independently against official sources relevant to the species, origin and destination. A favourable vulnerability score does not remove documentary requirements. The scientific article should not be treated as a regulatory certificate or as proof that a transfer is lawful.

Similarly, low relative vulnerability to collection does not demonstrate that an animal will thrive in an exhibit. Appropriate space, feeding, social conditions and staff expertise remain separate parts of the acquisition review. Bringing these considerations together is more useful than allowing one indicator to obscure the others.

Record the decision and its uncertainties

An acquisition record can include the assessment source, its date, the factors driving the ranking and the information still missing. This makes the decision easier to revisit when provenance, biological knowledge or captive-bred availability changes. It also supports consistent discussion between collection managers, veterinarians and suppliers.

Several limitations should remain explicit: older import records, estimates drawn from related species and the absence of direct assessment of each collected population. The interest statement identifies commercial partners in a doctoral scholarship and advisory, aquaculture-production or funding relationships between some authors and the aquarium trade. These relationships reinforce the need to compare the ranking with local evidence and to distinguish model outputs from purchasing claims.

A review should therefore ask whether the available evidence is adequate for the particular acquisition. Repeating a score without its assumptions would provide less useful scrutiny than a short, documented account of origin, collection pressure and unresolved questions.

Conclusion and support from Vetofish

Productivity–susceptibility analysis can help identify species that deserve closer attention before purchase. Its practical value comes from the checks it prompts on origin, reproduction and collection pressure. Converting it into a sustainability label would go beyond the evidence.

Vetofish offers technical advice and support for public aquariums. We can help teams develop a documented acquisition framework that considers conservation, aquatic health and the husbandry needs of the animals involved.