The state of knowledge on four families of Syngnathoidei fishes (Teleostei: Syngnathiformes): Aulostomidae, Centriscidae, Fistulariidae and Solenostomidae.

Knowledge on the ecology and life-history traits of coastal marine species is vital to inform their conservation and management, especially as their coastal habitats come under increasing threats. However, such data have never been collated for four of the five families in the suborder Syngnathoidei-the close relatives of the better-studied Syngnathidae (seahorses, pipefish and seadragons). Here, we present the first review of the state of knowledge on four families in the suborder Syngnathoidei: Aulostomidae (trumpetfish), Centriscidae (bellowsfish, snipefish and razorfish), Fistulariidae (cornetfish) and Solenostomidae (ghost pipefish). We analysed literature from a variety of repositories (n = 761 sources) and extracted information on these fishes' ecology, life-history traits, population parameters, uses and pressures. The families with the widest breadth of available information were Fistulariidae and Aulostomidae, whereas Centriscidae and Solenostomidae exhibited major data gaps across nearly all data fields. Across all families, morphologies, global ranges and maximum lengths are relatively well documented, whereas data concerning survival, reproduction and population metrics are extremely limited. This review uncovered information for all species which, to date, have not been considered in their International Union for Conservation of Nature (IUCN) Red List assessments, and highlighted data gaps which impede conservation planning. Our gap analysis provides an important call-to-action, establishing key research priorities to fill gaps in our understanding, to better inform future conservation assessments and management efforts for these distinctive but understudied fishes.