Invasive alien species (IAS) are introduced plants, animals and micro-organisms which, when spreading, represent serious threats to ecosystems, habitats or species, including humans. As a form of biological pollution, they represent the main threat to the country’s unique biological biodiversity. At least 21 introduced species of mammal, reptile and mollusc are naturalized in Mauritius with detrimental effects on native biodiversity. Examples: Javan deer, feral pigs, macaques, rats, Chinese guava and privet. Programmes are under way to enhance the control and management of IAS. These are implemented within the existing relevant legal and policy framework.   
We briefly highlight here some features of the legal and policy framework in place for the control and management of IAS and address the issue of its adequacy in providing the appropriate response to the threats posed by IAS.
The legal framework
Are there any gaps in the law that actually prevent effective control and management of IAS?
Until the coming into force of the Native Terrestrial Biodiversity and National Parks Act, 2015, we could list at least five pieces of legislation which had direct or indirect implications on IAS: the Plant Protection Act (2006), Forest and Reserves Act (1983), the Environment Protection Act (2002), the Fisheries and Marine Resources Act (2007) and the Animal Diseases Act (1925). The 2015 Act constitutes today an important piece of legislation for IAS control and management as it addresses issues, which were not covered by the other laws. What do the existing laws provide for?
The Native Terrestrial Biodiversity and National Parks Act, 2015 Act provides for the protection, conservation and management of native terrestrial biodiversity. Terrestrial biodiversity means biodiversity occurring on any land surface; and includes freshwater biodiversity. Marine biodiversity is not mentioned. However, the Act defines IAS to mean animals, micro-organisms and plants, which may threaten ecosystems, habitats, species and human beings without specifically restricting IAS to threats occurring on land.
The 2015 Act goes beyond the scope of the Plant Protection Act (2006)(PPA). The purpose of the PPA Act is essentially to prevent the introduction and to control the spread of plant pests. “Pest” is defined as any living agent capable of causing damage to any plant. Taken in its ordinary and wider sense, the phrase “capable of causing damage” can also be interpreted as to address the IAS threats.
Further, the National Plant Protection Office, the authority responsible for the enforcement of the PPA, implements the obligations of Mauritius under the International Plant Protection Convention (IPPC). This provision of the Act imports into the Mauritian legislation the full range of standards to be adhered to under the IPPC.
Also, in the PPA reference is made to ballast water as a medium capable of harbouring marine and aquatic and marine IAS. Given ballast water is considered as an important source of IAS, the PPA offers the legal provision for the control and management of IAS.
The PPA also provides for the control of imports of plants that do not fulfil phytosanitary requirements. The legal interpretation of phytosanitary relates to preventing the introduction and/or spread of pests. Therefore, in banning the import of plants that do not fulfil phytosanitary requirements, the Act can be interpreted as seeking to prevent the “introduction and/or spread of” IAS.
The Forests and Reserves Act 1983 provides for management of forests and resources.  IAS per se are not mentioned but the principle of control and management of IAS can be gathered from the reading of the different Sections of the Act. For example, the Act bans the introduction of any article or thing injurious to plant life on forest land or a mountain, river or nature reserve.
The Environment Protection Act (2002) is the main piece of legislation dealing with the protection of the environment and does apply to the control and management of IAS: an example would be the EIA certificate regime that is applicable for undertakings likely to represent threats to the environment. This would include such threats that arise from the spread of IAS. The Act also addresses the issue of  “spill” which is defined as a discharge of a pollutant into the environment from or out of a carrier or container, which poses a serious threat to the environment.
The Fisheries and Marine Resources Act 2007 provides for: the management, conservation, protection of fisheries and marine resources and protection of the marine ecosystems. It is an offence under the Act to throw, discharge into the maritime zones or into a river, lake, pond, canal, stream, tributary or wetland any poisonous substance. If an IAS can cause damage to marine biodiversity, can it be assimilated to a poisonous substance? The Act also provides for regulations to be made regarding conditions under which fish farming and fish ranching are to be carried out and measures for the protection of corals and shells, conservation and management of marine protected areas and artificial reefs.
The Animal diseases Act deals with the importation of animals. It provides for the inspection at various ports of entry of animals, suspected infected animals including animals in transit. It also provides for verification, control and quarantine of animals coming from abroad. Though there is no mention of IAS as such, the Act can be broadly interpreted as to mean control of IAS.  
Are there gaps in the law?
This question is best answered by institutions with a mandate in that area. If no instances are known whereby gaps in legislation have constituted a barrier to control and management of IAS, then there is no case for new legislation.
Nevertheless, there are situations generating IAS threats that are likely to occur in the near future, but for which no provisions in the law exist presently. In this context the imperatives of economic development may give rise to new situations with conflicting demands. For example, the development of the port sector, making of Port-Louis a hub, with increased activity, will imply more ships and hence more ballast water. The port development will also imply an expanded container services with the consequential risk of import of IAS.
Another set of questions would relate to the efficacy of the enforcement of existing legislation, the extent to which such enforcement measures are feasible or otherwise could be more efficiently implemented.
What about policy?
The approved policy for IAS is encompassed in the National Invasive Alien Species Strategy and Action Plan for the Republic of Mauritius: 2010-2019. It highlights the fact that institutional mandates regarding IAS issues in Mauritius are fragmented and spread across departments in different ministries. The document further suggests that coordination and cooperation between relevant institutions are necessary to address possible gaps, conflicts of interest, weaknesses and inconsistencies between the many legal, policy and institutional frameworks that address IAS.  
An important contribution of the NIASS relates to the issue of ballast water, which it describes as the most probable entry point for IAS into the national territory, and that there are currently no monitoring procedures to determine the origin of vessels or the number of potential invasive and harmful organisms they might harbour.
As Mauritius is envisaging to develop Port-Louis into a hub, and port movement will undoubtedly increase, thus escalating the risk in IAS importation from foreign ships, this situation will call for more stringent rules to tighten control to limit nuisance caused by dumping ballast water.          
Future development in the legal and policy framework should rather think about mainstreaming IAS control and management into existing sectoral documents rather than promoting the new stand-alone law.
One can use the Bio security Act as in Australia, which through mainstreaming, integrate elements of a biosecurity law which are not covered by the relevant  Mauritian legislation.
Regarding the issue of ballast water mainstreaming IAS in the Marine Shipping Act, the Fisheries Act and in the Environment Protection Act should be envisaged if no other avenues exist to have IAS control and management reinforced under the responsibility of shipping, fisheries and environment protection  authorities.
 The EIA (Environment Impact Assessment) regime should expressly refer to IAS threats posed by new undertakings. There is need for clarifications especially with new types of undertakings, e.g., pet trade, likely to cause IAS generated threats to the environment. For example, the catfish, introduced as pets have been released in rivers in Mauritius when their owners wanted to get rid of them, with consequential damage to freshwater life.