According to the International Union for Conservation of Nature (IUCN), some sea horse species are considered vulnerable to threatened, with population declines observed in many regions. For instance, the IUCN Red List classifies the following species as vulnerable:
1. Hippocampus comes (Lined sea horse): Found in the Western Pacific, this species is threatened by habitat destruction and overfishing.
2. Hippocampus trimaculatus (Three-spot sea horse): Native to the Indo-Pacific region, this sea horse is vulnerable to habitat loss and collection for traditional medicine.
3. Hippocampus hippocampus (Spiny sea horse): Distributed in the Mediterranean Sea and the Eastern Atlantic, this species faces threats from coastal development and fishing pressure.
4. Hippocampus erectus (Giraffe sea horse): Inhabiting the tropical waters of the Indo-Pacific, the giraffe sea horse is susceptible to habitat degradation and overfishing.
These estimates highlight the need for conservation efforts and sustainable management practices to protect sea horse populations and ensure their survival in the face of various threats they face.